{"id":24636,"date":"2021-09-21T07:00:09","date_gmt":"2021-09-21T06:00:09","guid":{"rendered":"https:\/\/intek-hifi.com\/?p=24636"},"modified":"2021-09-25T20:28:02","modified_gmt":"2021-09-25T19:28:02","slug":"nuprime-amg-sta-power-amplifier-and-amg-pra-preamplifier-tas-review","status":"publish","type":"post","link":"https:\/\/intek-hifi.com\/en\/nuprime-amg-sta-power-amplifier-and-amg-pra-preamplifier-tas-review\/","title":{"rendered":"NUPRIME AMG STA Power Amplifier and AMG PRA Preamplifier > TAS review"},"content":{"rendered":"

The company was founded back in 2014 by Jason Lim, the former CEO of NuForce, and it specializes in boutique Class D amps, media streamers, and many other products. I was very excited to get a nearly complete system of its AMG STA power amplifier and AMG PRA preamp. The amp and preamp combination have the same form factor and were clearly designed to work in tandem. While I\u2019m a fan of mixing and matching equipment from a wide range of manufacturers, there\u2019s something special about listening to the products from a single line, and getting a sense of\u00a0\u00a0<\/span>how they work in tandem.<\/p>\n


\n– – – – –
\nSticking with the dual-mono setup and the L600s, I put on the Tone Poets vinyl reissue of\u00a0My Point of View<\/i>\u00a0by Herbie Hancock. The tune \u201cKing Cobra\u201d opens the B-side, and it features Tony Williams at only 17 years old showing off all his incredible potential, with dancing cymbals that really sparkled through the STA\/PRA combo. Williams\u2019 fills sounded exuberant and rhythmically complex, and the system never compromised or slowed down his fascinating drumming. In the midrange, the piano and horns were smooth and silky with a hint of nice, heavy warmth down in their lower regions. Hancock\u2019s solo was quick and slithering, like the song\u2019s namesake, and each note was clearly delineated. Attacks and decays were on point, which added to the whole rhythmic picture building throughout the song. When the horns massed for the theme, each instrument remained wholly itself and focused, creating a wide sense of soundstage. The STA\/PRA dual-mono combo worked very well with the L600s, since the speakers have a very solid and deep lower end, and the amp\/preamp shines in the lower registers. It was that deep heft that really brought a difficult song like \u201cKing Cobra\u201d to life, and leant the entire ensemble a massive sound.
\n\u2013 Drew Kalbach, TAS | Sept, 2021<\/p>\n

Lint to products: NuPrime Audio<\/a>
\nLink to Review: The Absolute Sound<\/a><\/p>\n

 <\/p>","protected":false},"excerpt":{"rendered":"

The company was founded back in 2014 by Jason Lim, the former CEO of NuForce,…<\/p>","protected":false},"author":2,"featured_media":24637,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[171,175,173],"tags":[],"yoast_head":"\nNUPRIME AMG STA Power Amplifier and AMG PRA Preamplifier > TAS review - INTEK HI-FI<\/title>\n<meta name=\"description\" content=\"I don\u2019t have a ton of experience with NuPrime, but here\u2019s a quick, high-level history lesson: The company was founded back in 2014 by Jason Lim, the former CEO of NuForce, and it specializes in boutique Class D amps, media streamers, and many other products. I was very excited to get a nearly complete system of its AMG STA power amplifier and AMG PRA preamp. The amp and preamp combination have the same form factor and were clearly designed to work in tandem. While I\u2019m a fan of mixing and matching equipment from a wide range of manufacturers, there\u2019s something special about listening to the products from a single line, and getting a sense of how they work in tandem.Diving in, the NuPrime AMG STA ($1695) is a sleek, compact Class D power amplifier with a Class A preamp stage and linear power supply. The chassis is simple, with only a metal switch on the front for power, a small white LED indicator, and the NuPrime logo. My review sample came in dark gray, and looked good in my relatively tight equipment rack. As power amps go, the AMG STA never gets overly hot\u2014likely a product of its very efficient Class D output module\u2014though it does get somewhat warm. The back is relatively cramped, and it took a little contortion to get everything hooked up, but that didn\u2019t matter much once it was plugged it and powered on. The power amp supplies a solid 130Wpc into 8 ohms in stereo mode and 300Wpc into 8 ohms in mono mode. That\u2019s one of my favorite features of the PRA\u2014its ability to work as either a single stereo amplifier or in tandem with a second STA as part of a monoblock setup.The AMG PRA ($1795) looks almost exactly like the AMG STA power amp\u2014sorry for the vaguely confusing names\u2014but with two knobs and an LED indicator for channel and volume setting on the front panel. The left knob controls the unit\u2019s loudness compensation feature, which is something I\u2019ll talk about in a second. The right knob plays a bigger role\u2014push and hold for standby mode, push briefly to select inputs, and turn to adjust volume. Two toggles on the front switch between high and low gain and between normal and inverted phase. On the back, the PRA includes one set of balanced inputs and three unbalanced RCAs, along with a balanced and unbalanced out. The remote is heavy enough to break a toe if dropped and seems to be milled from solid aluminum; it performed all the functions I could possibly want\u2014from power to volume control to input switching. Overall, the PRA\u2019s design is simple, but attractive and effective.Before I dive into listening, it\u2019s time to look at the \u201cActive Low Frequency and Harmonic Gain\u201d control feature. To put it very simply, this knob is somewhat like Ye Olde Loudness switch of yore. When turned on it very noticeably boosts bass, without increasing the overall volume. It is an interesting EQ effect, and definitely achieves NuPrime\u2019s stated goal of giving smaller speakers a bit more natural low end. It worked well with my Wharfedale 225s, and actually sounded fairly nice with my Omen Dirty Weekend on its lowest setting. However, through the Polk L600 (review forthcoming), the knob made the bass a little too flabby, which makes sense. (The L600 have a very deep low end, and compensating made the bass a little too intense.) Each setting on the knob is a different EQ curve, and it may be worth experimenting with them to find the one that works best in your setup. For the following review, I kept the knob turned to the left, which turns the feature off. First up, I plugged in a single AMG STA amplifier with the AMG PRA preamp. (I was sent two STAs by NuPrime, so I did half my listening with one, and half with the dual-mono setup.) The single STA was more than enough to power my Zu Omen Dirty Weekends, and made my copy of the recent Ray Charles vinyl reissue Genius + Soul = Jazz sing and scream and shout. Lows were suitably solid, and the midrange really shone with an extremely pleasant smoothness. I never felt as though the AMG STA lagged behind or ran out of headroom powering the Zu DWs, even on this very dynamic recording. Ray Charles sounded fantastic, and his organ really grooved in tight and exciting lines. After trying the Zu DWs, I gave the Polk L600s a shot in the single AMG STA configuration. The Polk speakers are much more difficult to drive than the Zu DWs, but the STA still had plenty of space and headroom to blast through those fiery Ray Charles licks. I decided to try the Analogue Productions vinyl reissue of the RCA release Witches\u2019 Brew to see how it handled something dynamic that might stress its capabilities a bit. Even at its loudest, biggest moments, when the orchestra swells and cymbals crash, I never felt as though the AMG STA was lagging behind, even powering the difficult L600s. The low end was deep and slammed\u2014not quite razor-sharp but not flabby, either. The midrange had an ease to it, a nice, relaxed presentation. Horns were sharp and evenly spaced, and their upper registers had a bit of sparkle. Of the two speaker pairs I tried out, I\u2019d say the single AMG STA worked best with the Zu DWs, likely because they\u2019re easier to drive, but also because they share a similar sound profile\u2014relaxed, with a delightful midrange, a decently solid lower end, and a shimmery treble.I switched over to the dual-mono setup next, which gave me a solid 300Wpc into 8 ohms. That\u2019s way more than enough for the Zu Omen DWs, since they\u2019re easy to drive, but I liked the limitless-feeling headroom that the dual-mono combination bought me. I didn\u2019t find it necessarily sounded better, just more centered and solid, with no straining or restraint. Where this dual-mono configuration really worked was with the Polk L600s, the more difficult pair of speakers to drive. The AMG STA retained its signature relaxed and easy sound, but with that much power on tap really opened up the full potential of the Polks. The backgrounds were shockingly black, and it almost felt as if the AMG PRA preamp was nearly transparent, if you\u2019ll forgive a reviewing clich\u00e9. That deep noise floor allowed the music to shine with a crispness and dynamism that I absolutely loved.Sticking with the dual-mono setup and the L600s, I put on the Tone Poets vinyl reissue of My Point of View by Herbie Hancock. The tune \u201cKing Cobra\u201d opens the B-side, and it features Tony Williams at only 17 years old showing off all his incredible potential, with dancing cymbals that really sparkled through the STA\/PRA combo. Williams\u2019 fills sounded exuberant and rhythmically complex, and the system never compromised or slowed down his fascinating drumming. In the midrange, the piano and horns were smooth and silky with a hint of nice, heavy warmth down in their lower regions. Hancock\u2019s solo was quick and slithering, like the song\u2019s namesake, and each note was clearly delineated. Attacks and decays were on point, which added to the whole rhythmic picture building throughout the song. When the horns massed for the theme, each instrument remained wholly itself and focused, creating a wide sense of soundstage. The STA\/PRA dual-mono combo worked very well with the L600s, since the speakers have a very solid and deep lower end, and the amp\/preamp shines in the lower registers. It was that deep heft that really brought a difficult song like \u201cKing Cobra\u201d to life, and leant the entire ensemble a massive sound. Next up, I listened to Iceage\u2019s most recent album Seek Shelter, streamed via Tidal. On the opening track, \u201cShelter Song,\u201d the fuzzy guitar had a solid growl, while the deep kick drum slammed. The choir added depth and texture without ever straying into chaos. There was a surprisingly strong sense of place and positioning. Despite the sheer number of sounds occurring at the same time, I could still pinpoint each voice and instrument, and I think the monoblocks\u2019 massive amount of headroom went a long way to allowing the weight of the song to shine through. Later on the record, on the hard-rocking banger \u201cSaint Cecilia,\u201d the heavy guitars and screaming solos and choral shouts built into really epic, room-encompassing crescendos. The low end felt solid and intense, while the upper range of the twanging guitar had genuine dazzle. Overall, I felt the PRA\/STA combo played very nicely with some serious rock and roll.I really enjoyed the NuPrime AMG PRA preamplifier and the AMG STA power amplifier. I didn\u2019t waste any time hand-wringing over Class D, and barely even mention it in my review\u2014for good reason. The STA\/PRA combination sounded great, with a heavy low end, a relaxed and pleasant midrange, and just enough sparkle in the upper end to make cymbals shimmer. The interesting loudness function on the PRA and the very nicely made remote control were the kind of simple but useful upgrades over a standard preamp that made this combination feel premium. For many folks, I suspect a single STA will provide enough power, but for those who have more difficult-to-drive speakers, or those who want a massive amount of power on tap and ready to go, the monoblock setup is fantastic. This is a system worth trying and comes highly recommended.Specs & PricingAMG PRA PreamplifierFrequency response: 10Hz to 200kHz; +-0 to -0.1dBTHD: 0.008 %Input impedance: 1M ohm @10Hz\u2013200kHzS\/N: 95dBLoudness compensation: 2.2dB (125Hz)\/4.5dB (100Hz)\/5.3dB (75Hz)Gain: 3.2(High)\/2.1(Low)Inputs: 3x RCA, 1x balancedDimensions: 9.25\u2033 x 11.8\u2033 x 2.1\u2033Weight: 5.5 lbs.Price: $1795AMG STA Power AmplifierStereo power: 2x 130W at 8 ohms & 2x 200W at 4 ohmsMono power: 300W at 8 ohms & 320W at 4 ohmsPeak current: 10A\/15AGain: 26 (stereo) & 52 (mono)SNR: 100dB at 10WTHD+N: 0.006Frequency response: 10Hz\u201350kHz \u00b10.2dB at 8 ohmsInput impedance: 1M ohmSensitivity: 1.2Vrms stereo; 0.95Vrms monoDimensions: 9.25\u2033 x 11.3\u2033 x 2.1\u2033Weight: 8.8 lbs.Price: $1695 Skip to contentNuPrime AudioPRODUCTSProduct CategoriesProduct ListingShowroomsFrequently Asked QuestionsDiscontinuedHOW TO BUYRecommended SystemsA Beginner\u2019s Guide to Good AudioWhat Is High End Audio ?What Is High End DAC ?Amp Comparison & Sonic CharacteristicAmp Design & NuPrime\u2019s AdvantagesMQA & DACsWireless Audio Technology GuideCOMMUNITY & NEWSFacebook & InstagramCustomer BlogCommunity ForumTrade Shows & NewsWHERE TO BUYCONTACT & SUPPORTContact & SupportHelp DeskWarranty RegistrationFrequently Asked QuestionsSearch for:Search\u2026Home \/ Amplifier & PreampAMG PRAEUR 1,795.00The AMG PRA went beyond being a transparent preamp with 1M Ohm input impedance and the best analog source inputs. A user-selectable 4 stage \u201cActive Low Frequency and Harmonic Gain\u201d control gave it distinctive characteristics to enhance the speaker performance, a world-first in preamp design.Category: Amplifier & PreampTag: High-End Series DESCRIPTIONSPECSLOUDNESSREVIEWDOWNLOADThe AMG series front panel embodies its spirit. It is milled from a 15mm harden aerospace aluminum alloy using a four-axis CNC machine with a diamond cutter through a 48 steps process. Design elements such as the 3D \u201cfloating\u201d logo, the curved surface around the front panel switch, and diamond-cut edge bring the quality of ultra-high-end audio products to the affordable range of the AMG series.The design goal for AMG PRA was to deliver a transparent sounding analog preamp with its distinctive characteristics. Several new design concepts were developed and used in the AMG-PRE besides 1M\u03a9 input impedance to achieve the best analog inputs.Users of smallish speakers would often detect a distinct drop in bass response with some audio tracks. Instead of a simple \u201cBass Boost\u201d function that lifts a targeted low-frequency band, a user-selectable 4 stage \u201cActive Low Frequency and Harmonic Gain\u201d control compensates for the lack of bass presence. It achieves some bass extension and a more natural roll-off.Additional features such as the 2 stage gain control and invertible phase control increase the compatibility of the AMG-PRA with other power amplifiers.Technical DetailsThe layout of the AMG-PRA takes excellent care in isolating the sensitive audio signals from the power circuitry. The power circuitry comprising of a star topology power and ground layers is built on one board while a separate board houses the pre-amplification circuit. An isolation layer separates these two boards, which further minimizes interference. The effect is a highly transparent sound that is natural and not over etched.MUSES72320 Digital Volume ControlONE MEGA ultra-wide bandwidth low noise JFET, single-ended Class A input design and MUSES8920 Op-amp produce harmonics similar to vacuum tube amps, which has a \u201cwarm, airy and velvety\u201d sound characteristic.Non-feedback low-frequency domain Frequency Harmonic Modulation circuit provides minimum phase distortion and tone error.Inputs and outputs are fully balanced design.Front Panel SettingsLeft Toggle Switch: Output GainUpwards : High GainDownwards : Low GainRight Toggle Switch: Output PhaseUpwards : Phase InvertDownwards : Phase NormalLeft knob: Loudness CompensationTurn the knob to switch between Loudness CompensationRight Knob: Power and Input Selector and VolumesBriefly press for 3 sec to On\/Off standby modeBrief press to Input SelectorTurn the knob to adjust volumeAMG Remote ControlRELATED PRODUCTSAMPLIFIER & PREAMPAMG STAEUR 1,695.00The AMG STA comprises of several state-of-the-art innovations in power amp design. Its class-leading features include 1M Ohm input impedance, high instantaneous current for power delivery, 700kHz switching frequency, and Single-Ended Non-Negative Class A module coupled with Double Feedback Class D module for 300W mono amp power.ABOUT US NUPRIME-X NEWSLETTER PRIVACY POLICYCopyright 2021 \u00a9 Nuprime Audio, Inc. --- brand managed by Nuoem Pte. Ltd. Skip to contentBEYOND ORDINARYAbout UsNuPrime-XNewsletterPrivacy PolicyNuPrime AudioPRODUCTSProduct CategoriesProduct ListingShowroomsFrequently Asked QuestionsDiscontinuedHOW TO BUYRecommended SystemsA Beginner\u2019s Guide to Good AudioWhat Is High End Audio ?What Is High End DAC ?Amp Comparison & Sonic CharacteristicAmp Design & NuPrime\u2019s AdvantagesMQA & DACsWireless Audio Technology GuideCOMMUNITY & NEWSFacebook & InstagramCustomer BlogCommunity ForumTrade Shows & NewsWHERE TO BUYCONTACT & SUPPORTContact & SupportHelp DeskWarranty RegistrationFrequently Asked QuestionsSearch for:Search\u2026Home \/ Amplifier & PreampAMG STAEUR 1,695.00The AMG STA comprises of several state-of-the-art innovations in power amp design. Its class-leading features include 1M Ohm input impedance, high instantaneous current for power delivery, 700kHz switching frequency, and Single-Ended Non-Negative Class A module coupled with Double Feedback Class D module for 300W mono amp power.Category: Amplifier & PreampTag: AMG Series DESCRIPTIONSPECSFAQ & FORUMREVIEWDOWNLOADThe AMG series front panel embodies its spirit. It is milled from a 15mm harden aerospace aluminum alloy using a four-axis CNC machine with a diamond cutter through a 48 steps process. Design elements such as the 3D \u201cfloating\u201d logo, the curved surface around the front panel switch, and diamond-cut edge bring the quality of ultra-high-end audio products to the affordable range of the AMG series.TechnologyAMG STA PCB integrates ground wire shielding to isolate external interference. The 300 Mhz bandwidth JFET provides ultra-high input impedance and wide-band fast response. The dynamics of the design and the single-ended Class A circuit enriches the natural second harmonic.This design allows the most delicate details in the audio signal to carry through the chain. The level of transparency in sound reproduction is genuinely astonishing in this class of equipment, with a deft in creating a highly detailed sonic imagery.The AMG-STA uses the \u201cSingle-Ended, Non-Negative Feedback\u201d Class-A module partners with a new \u201cDouble feedback\u201d Class D circuitry. The Class D oscillating frequency has increased to 700kHz, which is 1.4 times that of the STA-9.Power CircuitThe power supply uses a 380W special winding power transformer, which has 30% more peak power output of a similar volume transformer.The AC power input from the Inlet Connector to the power transformer utilizes a high current welding line to provide maximum power transmission.Besides, high-frequency 3rd-order AC power filter reduces external noise.A 20A lock wire terminal block connects the transformer to the motherboard, in parallel with two10A peak current rectifiers.The main current path, adopting a large-capacity current design, uses a low-impedance copper plate to maximize power delivery to the amplifier circuits.How did AMG STA mono achieve better sonic characteristic, in addition to more power than AMG STA stereo ?The standard method for bridging a stereo amp into mono employs a series of op amps (OPA) in order to invert the input signals to one of the stereo amp, thereby creating an opposite phase, which can then be combined to increase power. Conversely, the AMG STA\u2019s innovative bridging circuit utilises a design we call Single-Ended Direct-Inject Bridge Technology, in which the mono mode, in addition to acquiring more than double the power, sounds livelier and more dynamic.Listening ImpressionWith improvements to every area, the bar has been raised for what is achievable with audio performance in small form factor.The AMG STA has a flavor of its own, so it is hard to compare it with the Evolution One, which derives some of its design from or the similarly priced ST-10. AMG STA sounded smooth and relaxing. Detail, resolution, dynamics, and speed are in the ST-10 ballpark, yet the sound is quite different.Drawing comparison with the Evolution One, they shared a trait of ease in reproducing the details of the recording comes afore. However, AMG STA does things differently. While the Evolution One has that inviting warmth, the AMG STA wants to allure the listener. Hence, instead of glitz and glamor, which pulls you in quickly into the performance, the AMG STA has a demeanor that slowly brings you into the music.Tonal qualities of the AMG STA leans toward being full and rich, so instruments and vocals seem to gain extra body, weight, and harmonic richness. It may not be the most accurate reproduction but does make Jazz and Vocal pieces highly addictive. It may take away the raw edge of Rock and Electronic music and sounds less exciting for some.The sound stage has an attractive characteristic. A linear presentation is like having floodlights shining on all the performers such that everyone can be seen equally well. The AMG STA, however, has more of a spotlighting effect, where performers are focused on getting your attention.It is tough to put the sound of the AMG STA into measurable attributes as the presentation is quite different from the other series. You\u2019ll need to try it and hear for yourself.RELATED PRODUCTSABOUT US NUPRIME-X NEWSLETTER PRIVACY POLICYCopyright 2021 \u00a9 Nuprime Audio, Inc. --- brand managed by Nuoem Pte. Ltd.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/intek-hifi.com\/en\/nuprime-amg-sta-power-amplifier-and-amg-pra-preamplifier-tas-review\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"NUPRIME AMG STA Power Amplifier and AMG PRA Preamplifier > TAS review - INTEK HI-FI\" \/>\n<meta property=\"og:description\" content=\"I don\u2019t have a ton of experience with NuPrime, but here\u2019s a quick, high-level history lesson: The company was founded back in 2014 by Jason Lim, the former CEO of NuForce, and it specializes in boutique Class D amps, media streamers, and many other products. I was very excited to get a nearly complete system of its AMG STA power amplifier and AMG PRA preamp. The amp and preamp combination have the same form factor and were clearly designed to work in tandem. While I\u2019m a fan of mixing and matching equipment from a wide range of manufacturers, there\u2019s something special about listening to the products from a single line, and getting a sense of how they work in tandem.Diving in, the NuPrime AMG STA ($1695) is a sleek, compact Class D power amplifier with a Class A preamp stage and linear power supply. The chassis is simple, with only a metal switch on the front for power, a small white LED indicator, and the NuPrime logo. My review sample came in dark gray, and looked good in my relatively tight equipment rack. As power amps go, the AMG STA never gets overly hot\u2014likely a product of its very efficient Class D output module\u2014though it does get somewhat warm. The back is relatively cramped, and it took a little contortion to get everything hooked up, but that didn\u2019t matter much once it was plugged it and powered on. The power amp supplies a solid 130Wpc into 8 ohms in stereo mode and 300Wpc into 8 ohms in mono mode. That\u2019s one of my favorite features of the PRA\u2014its ability to work as either a single stereo amplifier or in tandem with a second STA as part of a monoblock setup.The AMG PRA ($1795) looks almost exactly like the AMG STA power amp\u2014sorry for the vaguely confusing names\u2014but with two knobs and an LED indicator for channel and volume setting on the front panel. The left knob controls the unit\u2019s loudness compensation feature, which is something I\u2019ll talk about in a second. The right knob plays a bigger role\u2014push and hold for standby mode, push briefly to select inputs, and turn to adjust volume. Two toggles on the front switch between high and low gain and between normal and inverted phase. On the back, the PRA includes one set of balanced inputs and three unbalanced RCAs, along with a balanced and unbalanced out. The remote is heavy enough to break a toe if dropped and seems to be milled from solid aluminum; it performed all the functions I could possibly want\u2014from power to volume control to input switching. Overall, the PRA\u2019s design is simple, but attractive and effective.Before I dive into listening, it\u2019s time to look at the \u201cActive Low Frequency and Harmonic Gain\u201d control feature. To put it very simply, this knob is somewhat like Ye Olde Loudness switch of yore. When turned on it very noticeably boosts bass, without increasing the overall volume. It is an interesting EQ effect, and definitely achieves NuPrime\u2019s stated goal of giving smaller speakers a bit more natural low end. It worked well with my Wharfedale 225s, and actually sounded fairly nice with my Omen Dirty Weekend on its lowest setting. However, through the Polk L600 (review forthcoming), the knob made the bass a little too flabby, which makes sense. (The L600 have a very deep low end, and compensating made the bass a little too intense.) Each setting on the knob is a different EQ curve, and it may be worth experimenting with them to find the one that works best in your setup. For the following review, I kept the knob turned to the left, which turns the feature off. First up, I plugged in a single AMG STA amplifier with the AMG PRA preamp. (I was sent two STAs by NuPrime, so I did half my listening with one, and half with the dual-mono setup.) The single STA was more than enough to power my Zu Omen Dirty Weekends, and made my copy of the recent Ray Charles vinyl reissue Genius + Soul = Jazz sing and scream and shout. Lows were suitably solid, and the midrange really shone with an extremely pleasant smoothness. I never felt as though the AMG STA lagged behind or ran out of headroom powering the Zu DWs, even on this very dynamic recording. Ray Charles sounded fantastic, and his organ really grooved in tight and exciting lines. After trying the Zu DWs, I gave the Polk L600s a shot in the single AMG STA configuration. The Polk speakers are much more difficult to drive than the Zu DWs, but the STA still had plenty of space and headroom to blast through those fiery Ray Charles licks. I decided to try the Analogue Productions vinyl reissue of the RCA release Witches\u2019 Brew to see how it handled something dynamic that might stress its capabilities a bit. Even at its loudest, biggest moments, when the orchestra swells and cymbals crash, I never felt as though the AMG STA was lagging behind, even powering the difficult L600s. The low end was deep and slammed\u2014not quite razor-sharp but not flabby, either. The midrange had an ease to it, a nice, relaxed presentation. Horns were sharp and evenly spaced, and their upper registers had a bit of sparkle. Of the two speaker pairs I tried out, I\u2019d say the single AMG STA worked best with the Zu DWs, likely because they\u2019re easier to drive, but also because they share a similar sound profile\u2014relaxed, with a delightful midrange, a decently solid lower end, and a shimmery treble.I switched over to the dual-mono setup next, which gave me a solid 300Wpc into 8 ohms. That\u2019s way more than enough for the Zu Omen DWs, since they\u2019re easy to drive, but I liked the limitless-feeling headroom that the dual-mono combination bought me. I didn\u2019t find it necessarily sounded better, just more centered and solid, with no straining or restraint. Where this dual-mono configuration really worked was with the Polk L600s, the more difficult pair of speakers to drive. The AMG STA retained its signature relaxed and easy sound, but with that much power on tap really opened up the full potential of the Polks. The backgrounds were shockingly black, and it almost felt as if the AMG PRA preamp was nearly transparent, if you\u2019ll forgive a reviewing clich\u00e9. That deep noise floor allowed the music to shine with a crispness and dynamism that I absolutely loved.Sticking with the dual-mono setup and the L600s, I put on the Tone Poets vinyl reissue of My Point of View by Herbie Hancock. The tune \u201cKing Cobra\u201d opens the B-side, and it features Tony Williams at only 17 years old showing off all his incredible potential, with dancing cymbals that really sparkled through the STA\/PRA combo. Williams\u2019 fills sounded exuberant and rhythmically complex, and the system never compromised or slowed down his fascinating drumming. In the midrange, the piano and horns were smooth and silky with a hint of nice, heavy warmth down in their lower regions. Hancock\u2019s solo was quick and slithering, like the song\u2019s namesake, and each note was clearly delineated. Attacks and decays were on point, which added to the whole rhythmic picture building throughout the song. When the horns massed for the theme, each instrument remained wholly itself and focused, creating a wide sense of soundstage. The STA\/PRA dual-mono combo worked very well with the L600s, since the speakers have a very solid and deep lower end, and the amp\/preamp shines in the lower registers. It was that deep heft that really brought a difficult song like \u201cKing Cobra\u201d to life, and leant the entire ensemble a massive sound. Next up, I listened to Iceage\u2019s most recent album Seek Shelter, streamed via Tidal. On the opening track, \u201cShelter Song,\u201d the fuzzy guitar had a solid growl, while the deep kick drum slammed. The choir added depth and texture without ever straying into chaos. There was a surprisingly strong sense of place and positioning. Despite the sheer number of sounds occurring at the same time, I could still pinpoint each voice and instrument, and I think the monoblocks\u2019 massive amount of headroom went a long way to allowing the weight of the song to shine through. Later on the record, on the hard-rocking banger \u201cSaint Cecilia,\u201d the heavy guitars and screaming solos and choral shouts built into really epic, room-encompassing crescendos. The low end felt solid and intense, while the upper range of the twanging guitar had genuine dazzle. Overall, I felt the PRA\/STA combo played very nicely with some serious rock and roll.I really enjoyed the NuPrime AMG PRA preamplifier and the AMG STA power amplifier. I didn\u2019t waste any time hand-wringing over Class D, and barely even mention it in my review\u2014for good reason. The STA\/PRA combination sounded great, with a heavy low end, a relaxed and pleasant midrange, and just enough sparkle in the upper end to make cymbals shimmer. The interesting loudness function on the PRA and the very nicely made remote control were the kind of simple but useful upgrades over a standard preamp that made this combination feel premium. For many folks, I suspect a single STA will provide enough power, but for those who have more difficult-to-drive speakers, or those who want a massive amount of power on tap and ready to go, the monoblock setup is fantastic. This is a system worth trying and comes highly recommended.Specs & PricingAMG PRA PreamplifierFrequency response: 10Hz to 200kHz; +-0 to -0.1dBTHD: 0.008 %Input impedance: 1M ohm @10Hz\u2013200kHzS\/N: 95dBLoudness compensation: 2.2dB (125Hz)\/4.5dB (100Hz)\/5.3dB (75Hz)Gain: 3.2(High)\/2.1(Low)Inputs: 3x RCA, 1x balancedDimensions: 9.25\u2033 x 11.8\u2033 x 2.1\u2033Weight: 5.5 lbs.Price: $1795AMG STA Power AmplifierStereo power: 2x 130W at 8 ohms & 2x 200W at 4 ohmsMono power: 300W at 8 ohms & 320W at 4 ohmsPeak current: 10A\/15AGain: 26 (stereo) & 52 (mono)SNR: 100dB at 10WTHD+N: 0.006Frequency response: 10Hz\u201350kHz \u00b10.2dB at 8 ohmsInput impedance: 1M ohmSensitivity: 1.2Vrms stereo; 0.95Vrms monoDimensions: 9.25\u2033 x 11.3\u2033 x 2.1\u2033Weight: 8.8 lbs.Price: $1695 Skip to contentNuPrime AudioPRODUCTSProduct CategoriesProduct ListingShowroomsFrequently Asked QuestionsDiscontinuedHOW TO BUYRecommended SystemsA Beginner\u2019s Guide to Good AudioWhat Is High End Audio ?What Is High End DAC ?Amp Comparison & Sonic CharacteristicAmp Design & NuPrime\u2019s AdvantagesMQA & DACsWireless Audio Technology GuideCOMMUNITY & NEWSFacebook & InstagramCustomer BlogCommunity ForumTrade Shows & NewsWHERE TO BUYCONTACT & SUPPORTContact & SupportHelp DeskWarranty RegistrationFrequently Asked QuestionsSearch for:Search\u2026Home \/ Amplifier & PreampAMG PRAEUR 1,795.00The AMG PRA went beyond being a transparent preamp with 1M Ohm input impedance and the best analog source inputs. A user-selectable 4 stage \u201cActive Low Frequency and Harmonic Gain\u201d control gave it distinctive characteristics to enhance the speaker performance, a world-first in preamp design.Category: Amplifier & PreampTag: High-End Series DESCRIPTIONSPECSLOUDNESSREVIEWDOWNLOADThe AMG series front panel embodies its spirit. It is milled from a 15mm harden aerospace aluminum alloy using a four-axis CNC machine with a diamond cutter through a 48 steps process. Design elements such as the 3D \u201cfloating\u201d logo, the curved surface around the front panel switch, and diamond-cut edge bring the quality of ultra-high-end audio products to the affordable range of the AMG series.The design goal for AMG PRA was to deliver a transparent sounding analog preamp with its distinctive characteristics. Several new design concepts were developed and used in the AMG-PRE besides 1M\u03a9 input impedance to achieve the best analog inputs.Users of smallish speakers would often detect a distinct drop in bass response with some audio tracks. Instead of a simple \u201cBass Boost\u201d function that lifts a targeted low-frequency band, a user-selectable 4 stage \u201cActive Low Frequency and Harmonic Gain\u201d control compensates for the lack of bass presence. It achieves some bass extension and a more natural roll-off.Additional features such as the 2 stage gain control and invertible phase control increase the compatibility of the AMG-PRA with other power amplifiers.Technical DetailsThe layout of the AMG-PRA takes excellent care in isolating the sensitive audio signals from the power circuitry. The power circuitry comprising of a star topology power and ground layers is built on one board while a separate board houses the pre-amplification circuit. An isolation layer separates these two boards, which further minimizes interference. The effect is a highly transparent sound that is natural and not over etched.MUSES72320 Digital Volume ControlONE MEGA ultra-wide bandwidth low noise JFET, single-ended Class A input design and MUSES8920 Op-amp produce harmonics similar to vacuum tube amps, which has a \u201cwarm, airy and velvety\u201d sound characteristic.Non-feedback low-frequency domain Frequency Harmonic Modulation circuit provides minimum phase distortion and tone error.Inputs and outputs are fully balanced design.Front Panel SettingsLeft Toggle Switch: Output GainUpwards : High GainDownwards : Low GainRight Toggle Switch: Output PhaseUpwards : Phase InvertDownwards : Phase NormalLeft knob: Loudness CompensationTurn the knob to switch between Loudness CompensationRight Knob: Power and Input Selector and VolumesBriefly press for 3 sec to On\/Off standby modeBrief press to Input SelectorTurn the knob to adjust volumeAMG Remote ControlRELATED PRODUCTSAMPLIFIER & PREAMPAMG STAEUR 1,695.00The AMG STA comprises of several state-of-the-art innovations in power amp design. Its class-leading features include 1M Ohm input impedance, high instantaneous current for power delivery, 700kHz switching frequency, and Single-Ended Non-Negative Class A module coupled with Double Feedback Class D module for 300W mono amp power.ABOUT US NUPRIME-X NEWSLETTER PRIVACY POLICYCopyright 2021 \u00a9 Nuprime Audio, Inc. --- brand managed by Nuoem Pte. Ltd. Skip to contentBEYOND ORDINARYAbout UsNuPrime-XNewsletterPrivacy PolicyNuPrime AudioPRODUCTSProduct CategoriesProduct ListingShowroomsFrequently Asked QuestionsDiscontinuedHOW TO BUYRecommended SystemsA Beginner\u2019s Guide to Good AudioWhat Is High End Audio ?What Is High End DAC ?Amp Comparison & Sonic CharacteristicAmp Design & NuPrime\u2019s AdvantagesMQA & DACsWireless Audio Technology GuideCOMMUNITY & NEWSFacebook & InstagramCustomer BlogCommunity ForumTrade Shows & NewsWHERE TO BUYCONTACT & SUPPORTContact & SupportHelp DeskWarranty RegistrationFrequently Asked QuestionsSearch for:Search\u2026Home \/ Amplifier & PreampAMG STAEUR 1,695.00The AMG STA comprises of several state-of-the-art innovations in power amp design. Its class-leading features include 1M Ohm input impedance, high instantaneous current for power delivery, 700kHz switching frequency, and Single-Ended Non-Negative Class A module coupled with Double Feedback Class D module for 300W mono amp power.Category: Amplifier & PreampTag: AMG Series DESCRIPTIONSPECSFAQ & FORUMREVIEWDOWNLOADThe AMG series front panel embodies its spirit. It is milled from a 15mm harden aerospace aluminum alloy using a four-axis CNC machine with a diamond cutter through a 48 steps process. Design elements such as the 3D \u201cfloating\u201d logo, the curved surface around the front panel switch, and diamond-cut edge bring the quality of ultra-high-end audio products to the affordable range of the AMG series.TechnologyAMG STA PCB integrates ground wire shielding to isolate external interference. The 300 Mhz bandwidth JFET provides ultra-high input impedance and wide-band fast response. The dynamics of the design and the single-ended Class A circuit enriches the natural second harmonic.This design allows the most delicate details in the audio signal to carry through the chain. The level of transparency in sound reproduction is genuinely astonishing in this class of equipment, with a deft in creating a highly detailed sonic imagery.The AMG-STA uses the \u201cSingle-Ended, Non-Negative Feedback\u201d Class-A module partners with a new \u201cDouble feedback\u201d Class D circuitry. The Class D oscillating frequency has increased to 700kHz, which is 1.4 times that of the STA-9.Power CircuitThe power supply uses a 380W special winding power transformer, which has 30% more peak power output of a similar volume transformer.The AC power input from the Inlet Connector to the power transformer utilizes a high current welding line to provide maximum power transmission.Besides, high-frequency 3rd-order AC power filter reduces external noise.A 20A lock wire terminal block connects the transformer to the motherboard, in parallel with two10A peak current rectifiers.The main current path, adopting a large-capacity current design, uses a low-impedance copper plate to maximize power delivery to the amplifier circuits.How did AMG STA mono achieve better sonic characteristic, in addition to more power than AMG STA stereo ?The standard method for bridging a stereo amp into mono employs a series of op amps (OPA) in order to invert the input signals to one of the stereo amp, thereby creating an opposite phase, which can then be combined to increase power. Conversely, the AMG STA\u2019s innovative bridging circuit utilises a design we call Single-Ended Direct-Inject Bridge Technology, in which the mono mode, in addition to acquiring more than double the power, sounds livelier and more dynamic.Listening ImpressionWith improvements to every area, the bar has been raised for what is achievable with audio performance in small form factor.The AMG STA has a flavor of its own, so it is hard to compare it with the Evolution One, which derives some of its design from or the similarly priced ST-10. AMG STA sounded smooth and relaxing. Detail, resolution, dynamics, and speed are in the ST-10 ballpark, yet the sound is quite different.Drawing comparison with the Evolution One, they shared a trait of ease in reproducing the details of the recording comes afore. However, AMG STA does things differently. While the Evolution One has that inviting warmth, the AMG STA wants to allure the listener. Hence, instead of glitz and glamor, which pulls you in quickly into the performance, the AMG STA has a demeanor that slowly brings you into the music.Tonal qualities of the AMG STA leans toward being full and rich, so instruments and vocals seem to gain extra body, weight, and harmonic richness. It may not be the most accurate reproduction but does make Jazz and Vocal pieces highly addictive. It may take away the raw edge of Rock and Electronic music and sounds less exciting for some.The sound stage has an attractive characteristic. A linear presentation is like having floodlights shining on all the performers such that everyone can be seen equally well. The AMG STA, however, has more of a spotlighting effect, where performers are focused on getting your attention.It is tough to put the sound of the AMG STA into measurable attributes as the presentation is quite different from the other series. You\u2019ll need to try it and hear for yourself.RELATED PRODUCTSABOUT US NUPRIME-X NEWSLETTER PRIVACY POLICYCopyright 2021 \u00a9 Nuprime Audio, Inc. --- brand managed by Nuoem Pte. Ltd.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/intek-hifi.com\/en\/nuprime-amg-sta-power-amplifier-and-amg-pra-preamplifier-tas-review\/\" \/>\n<meta property=\"og:site_name\" content=\"INTEK HI-FI\" \/>\n<meta property=\"article:published_time\" content=\"2021-09-21T06:00:09+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2021-09-25T19:28:02+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/intek-hifi.com\/wp-content\/uploads\/2021\/09\/nuprime-audio-amg-1280x720-1.jpg\" \/>\n\t<meta property=\"og:image:width\" content=\"1280\" \/>\n\t<meta property=\"og:image:height\" content=\"720\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"darko\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"2 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"WebSite\",\"@id\":\"https:\/\/intek-hifi.com\/#website\",\"url\":\"https:\/\/intek-hifi.com\/\",\"name\":\"INTEK HI-FI\",\"description\":\"\",\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\/\/intek-hifi.com\/?s={search_term_string}\"},\"query-input\":\"required name=search_term_string\"}],\"inLanguage\":\"en-US\"},{\"@type\":\"ImageObject\",\"@id\":\"https:\/\/intek-hifi.com\/nuprime-amg-sta-power-amplifier-and-amg-pra-preamplifier-tas-review\/#primaryimage\",\"inLanguage\":\"en-US\",\"url\":\"https:\/\/intek-hifi.com\/wp-content\/uploads\/2021\/09\/nuprime-audio-amg-1280x720-1.jpg\",\"contentUrl\":\"https:\/\/intek-hifi.com\/wp-content\/uploads\/2021\/09\/nuprime-audio-amg-1280x720-1.jpg\",\"width\":1280,\"height\":720},{\"@type\":\"WebPage\",\"@id\":\"https:\/\/intek-hifi.com\/nuprime-amg-sta-power-amplifier-and-amg-pra-preamplifier-tas-review\/#webpage\",\"url\":\"https:\/\/intek-hifi.com\/nuprime-amg-sta-power-amplifier-and-amg-pra-preamplifier-tas-review\/\",\"name\":\"NUPRIME AMG STA Power Amplifier and AMG PRA Preamplifier > TAS review - INTEK HI-FI\",\"isPartOf\":{\"@id\":\"https:\/\/intek-hifi.com\/#website\"},\"primaryImageOfPage\":{\"@id\":\"https:\/\/intek-hifi.com\/nuprime-amg-sta-power-amplifier-and-amg-pra-preamplifier-tas-review\/#primaryimage\"},\"datePublished\":\"2021-09-21T06:00:09+00:00\",\"dateModified\":\"2021-09-25T19:28:02+00:00\",\"author\":{\"@id\":\"https:\/\/intek-hifi.com\/#\/schema\/person\/02fa1742be92272c2fe50f2579f320e7\"},\"description\":\"I don\\u2019t have a ton of experience with NuPrime, but here\\u2019s a quick, high-level history lesson: The company was founded back in 2014 by Jason Lim, the former CEO of NuForce, and it specializes in boutique Class D amps, media streamers, and many other products. I was very excited to get a nearly complete system of its AMG STA power amplifier and AMG PRA preamp. The amp and preamp combination have the same form factor and were clearly designed to work in tandem. While I\\u2019m a fan of mixing and matching equipment from a wide range of manufacturers, there\\u2019s something special about listening to the products from a single line, and getting a sense of how they work in tandem.Diving in, the NuPrime AMG STA ($1695) is a sleek, compact Class D power amplifier with a Class A preamp stage and linear power supply. The chassis is simple, with only a metal switch on the front for power, a small white LED indicator, and the NuPrime logo. My review sample came in dark gray, and looked good in my relatively tight equipment rack. As power amps go, the AMG STA never gets overly hot\\u2014likely a product of its very efficient Class D output module\\u2014though it does get somewhat warm. The back is relatively cramped, and it took a little contortion to get everything hooked up, but that didn\\u2019t matter much once it was plugged it and powered on. The power amp supplies a solid 130Wpc into 8 ohms in stereo mode and 300Wpc into 8 ohms in mono mode. That\\u2019s one of my favorite features of the PRA\\u2014its ability to work as either a single stereo amplifier or in tandem with a second STA as part of a monoblock setup.The AMG PRA ($1795) looks almost exactly like the AMG STA power amp\\u2014sorry for the vaguely confusing names\\u2014but with two knobs and an LED indicator for channel and volume setting on the front panel. The left knob controls the unit\\u2019s loudness compensation feature, which is something I\\u2019ll talk about in a second. The right knob plays a bigger role\\u2014push and hold for standby mode, push briefly to select inputs, and turn to adjust volume. Two toggles on the front switch between high and low gain and between normal and inverted phase. On the back, the PRA includes one set of balanced inputs and three unbalanced RCAs, along with a balanced and unbalanced out. The remote is heavy enough to break a toe if dropped and seems to be milled from solid aluminum; it performed all the functions I could possibly want\\u2014from power to volume control to input switching. Overall, the PRA\\u2019s design is simple, but attractive and effective.Before I dive into listening, it\\u2019s time to look at the \\u201cActive Low Frequency and Harmonic Gain\\u201d control feature. To put it very simply, this knob is somewhat like Ye Olde Loudness switch of yore. When turned on it very noticeably boosts bass, without increasing the overall volume. It is an interesting EQ effect, and definitely achieves NuPrime\\u2019s stated goal of giving smaller speakers a bit more natural low end. It worked well with my Wharfedale 225s, and actually sounded fairly nice with my Omen Dirty Weekend on its lowest setting. However, through the Polk L600 (review forthcoming), the knob made the bass a little too flabby, which makes sense. (The L600 have a very deep low end, and compensating made the bass a little too intense.) Each setting on the knob is a different EQ curve, and it may be worth experimenting with them to find the one that works best in your setup. For the following review, I kept the knob turned to the left, which turns the feature off. First up, I plugged in a single AMG STA amplifier with the AMG PRA preamp. (I was sent two STAs by NuPrime, so I did half my listening with one, and half with the dual-mono setup.) The single STA was more than enough to power my Zu Omen Dirty Weekends, and made my copy of the recent Ray Charles vinyl reissue Genius + Soul = Jazz sing and scream and shout. Lows were suitably solid, and the midrange really shone with an extremely pleasant smoothness. I never felt as though the AMG STA lagged behind or ran out of headroom powering the Zu DWs, even on this very dynamic recording. Ray Charles sounded fantastic, and his organ really grooved in tight and exciting lines. After trying the Zu DWs, I gave the Polk L600s a shot in the single AMG STA configuration. The Polk speakers are much more difficult to drive than the Zu DWs, but the STA still had plenty of space and headroom to blast through those fiery Ray Charles licks. I decided to try the Analogue Productions vinyl reissue of the RCA release Witches\\u2019 Brew to see how it handled something dynamic that might stress its capabilities a bit. Even at its loudest, biggest moments, when the orchestra swells and cymbals crash, I never felt as though the AMG STA was lagging behind, even powering the difficult L600s. The low end was deep and slammed\\u2014not quite razor-sharp but not flabby, either. The midrange had an ease to it, a nice, relaxed presentation. Horns were sharp and evenly spaced, and their upper registers had a bit of sparkle. Of the two speaker pairs I tried out, I\\u2019d say the single AMG STA worked best with the Zu DWs, likely because they\\u2019re easier to drive, but also because they share a similar sound profile\\u2014relaxed, with a delightful midrange, a decently solid lower end, and a shimmery treble.I switched over to the dual-mono setup next, which gave me a solid 300Wpc into 8 ohms. That\\u2019s way more than enough for the Zu Omen DWs, since they\\u2019re easy to drive, but I liked the limitless-feeling headroom that the dual-mono combination bought me. I didn\\u2019t find it necessarily sounded better, just more centered and solid, with no straining or restraint. Where this dual-mono configuration really worked was with the Polk L600s, the more difficult pair of speakers to drive. The AMG STA retained its signature relaxed and easy sound, but with that much power on tap really opened up the full potential of the Polks. The backgrounds were shockingly black, and it almost felt as if the AMG PRA preamp was nearly transparent, if you\\u2019ll forgive a reviewing clich\\u00e9. That deep noise floor allowed the music to shine with a crispness and dynamism that I absolutely loved.Sticking with the dual-mono setup and the L600s, I put on the Tone Poets vinyl reissue of My Point of View by Herbie Hancock. The tune \\u201cKing Cobra\\u201d opens the B-side, and it features Tony Williams at only 17 years old showing off all his incredible potential, with dancing cymbals that really sparkled through the STA\/PRA combo. Williams\\u2019 fills sounded exuberant and rhythmically complex, and the system never compromised or slowed down his fascinating drumming. In the midrange, the piano and horns were smooth and silky with a hint of nice, heavy warmth down in their lower regions. Hancock\\u2019s solo was quick and slithering, like the song\\u2019s namesake, and each note was clearly delineated. Attacks and decays were on point, which added to the whole rhythmic picture building throughout the song. When the horns massed for the theme, each instrument remained wholly itself and focused, creating a wide sense of soundstage. The STA\/PRA dual-mono combo worked very well with the L600s, since the speakers have a very solid and deep lower end, and the amp\/preamp shines in the lower registers. It was that deep heft that really brought a difficult song like \\u201cKing Cobra\\u201d to life, and leant the entire ensemble a massive sound. Next up, I listened to Iceage\\u2019s most recent album Seek Shelter, streamed via Tidal. On the opening track, \\u201cShelter Song,\\u201d the fuzzy guitar had a solid growl, while the deep kick drum slammed. The choir added depth and texture without ever straying into chaos. There was a surprisingly strong sense of place and positioning. Despite the sheer number of sounds occurring at the same time, I could still pinpoint each voice and instrument, and I think the monoblocks\\u2019 massive amount of headroom went a long way to allowing the weight of the song to shine through. Later on the record, on the hard-rocking banger \\u201cSaint Cecilia,\\u201d the heavy guitars and screaming solos and choral shouts built into really epic, room-encompassing crescendos. The low end felt solid and intense, while the upper range of the twanging guitar had genuine dazzle. Overall, I felt the PRA\/STA combo played very nicely with some serious rock and roll.I really enjoyed the NuPrime AMG PRA preamplifier and the AMG STA power amplifier. I didn\\u2019t waste any time hand-wringing over Class D, and barely even mention it in my review\\u2014for good reason. The STA\/PRA combination sounded great, with a heavy low end, a relaxed and pleasant midrange, and just enough sparkle in the upper end to make cymbals shimmer. The interesting loudness function on the PRA and the very nicely made remote control were the kind of simple but useful upgrades over a standard preamp that made this combination feel premium. For many folks, I suspect a single STA will provide enough power, but for those who have more difficult-to-drive speakers, or those who want a massive amount of power on tap and ready to go, the monoblock setup is fantastic. This is a system worth trying and comes highly recommended.Specs & PricingAMG PRA PreamplifierFrequency response: 10Hz to 200kHz; +-0 to -0.1dBTHD: 0.008 %Input impedance: 1M ohm @10Hz\\u2013200kHzS\/N: 95dBLoudness compensation: 2.2dB (125Hz)\/4.5dB (100Hz)\/5.3dB (75Hz)Gain: 3.2(High)\/2.1(Low)Inputs: 3x RCA, 1x balancedDimensions: 9.25\\u2033 x 11.8\\u2033 x 2.1\\u2033Weight: 5.5 lbs.Price: $1795AMG STA Power AmplifierStereo power: 2x 130W at 8 ohms & 2x 200W at 4 ohmsMono power: 300W at 8 ohms & 320W at 4 ohmsPeak current: 10A\/15AGain: 26 (stereo) & 52 (mono)SNR: 100dB at 10WTHD+N: 0.006Frequency response: 10Hz\\u201350kHz \\u00b10.2dB at 8 ohmsInput impedance: 1M ohmSensitivity: 1.2Vrms stereo; 0.95Vrms monoDimensions: 9.25\\u2033 x 11.3\\u2033 x 2.1\\u2033Weight: 8.8 lbs.Price: $1695 Skip to contentNuPrime AudioPRODUCTSProduct CategoriesProduct ListingShowroomsFrequently Asked QuestionsDiscontinuedHOW TO BUYRecommended SystemsA Beginner\\u2019s Guide to Good AudioWhat Is High End Audio ?What Is High End DAC ?Amp Comparison & Sonic CharacteristicAmp Design & NuPrime\\u2019s AdvantagesMQA & DACsWireless Audio Technology GuideCOMMUNITY & NEWSFacebook & InstagramCustomer BlogCommunity ForumTrade Shows & NewsWHERE TO BUYCONTACT & SUPPORTContact & SupportHelp DeskWarranty RegistrationFrequently Asked QuestionsSearch for:Search\\u2026Home \/ Amplifier & PreampAMG PRAEUR 1,795.00The AMG PRA went beyond being a transparent preamp with 1M Ohm input impedance and the best analog source inputs. A user-selectable 4 stage \\u201cActive Low Frequency and Harmonic Gain\\u201d control gave it distinctive characteristics to enhance the speaker performance, a world-first in preamp design.Category: Amplifier & PreampTag: High-End Series DESCRIPTIONSPECSLOUDNESSREVIEWDOWNLOADThe AMG series front panel embodies its spirit. It is milled from a 15mm harden aerospace aluminum alloy using a four-axis CNC machine with a diamond cutter through a 48 steps process. Design elements such as the 3D \\u201cfloating\\u201d logo, the curved surface around the front panel switch, and diamond-cut edge bring the quality of ultra-high-end audio products to the affordable range of the AMG series.The design goal for AMG PRA was to deliver a transparent sounding analog preamp with its distinctive characteristics. Several new design concepts were developed and used in the AMG-PRE besides 1M\\u03a9 input impedance to achieve the best analog inputs.Users of smallish speakers would often detect a distinct drop in bass response with some audio tracks. Instead of a simple \\u201cBass Boost\\u201d function that lifts a targeted low-frequency band, a user-selectable 4 stage \\u201cActive Low Frequency and Harmonic Gain\\u201d control compensates for the lack of bass presence. It achieves some bass extension and a more natural roll-off.Additional features such as the 2 stage gain control and invertible phase control increase the compatibility of the AMG-PRA with other power amplifiers.Technical DetailsThe layout of the AMG-PRA takes excellent care in isolating the sensitive audio signals from the power circuitry. The power circuitry comprising of a star topology power and ground layers is built on one board while a separate board houses the pre-amplification circuit. An isolation layer separates these two boards, which further minimizes interference. The effect is a highly transparent sound that is natural and not over etched.MUSES72320 Digital Volume ControlONE MEGA ultra-wide bandwidth low noise JFET, single-ended Class A input design and MUSES8920 Op-amp produce harmonics similar to vacuum tube amps, which has a \\u201cwarm, airy and velvety\\u201d sound characteristic.Non-feedback low-frequency domain Frequency Harmonic Modulation circuit provides minimum phase distortion and tone error.Inputs and outputs are fully balanced design.Front Panel SettingsLeft Toggle Switch: Output GainUpwards : High GainDownwards : Low GainRight Toggle Switch: Output PhaseUpwards : Phase InvertDownwards : Phase NormalLeft knob: Loudness CompensationTurn the knob to switch between Loudness CompensationRight Knob: Power and Input Selector and VolumesBriefly press for 3 sec to On\/Off standby modeBrief press to Input SelectorTurn the knob to adjust volumeAMG Remote ControlRELATED PRODUCTSAMPLIFIER & PREAMPAMG STAEUR 1,695.00The AMG STA comprises of several state-of-the-art innovations in power amp design. Its class-leading features include 1M Ohm input impedance, high instantaneous current for power delivery, 700kHz switching frequency, and Single-Ended Non-Negative Class A module coupled with Double Feedback Class D module for 300W mono amp power.ABOUT US NUPRIME-X NEWSLETTER PRIVACY POLICYCopyright 2021 \\u00a9 Nuprime Audio, Inc. --- brand managed by Nuoem Pte. Ltd. Skip to contentBEYOND ORDINARYAbout UsNuPrime-XNewsletterPrivacy PolicyNuPrime AudioPRODUCTSProduct CategoriesProduct ListingShowroomsFrequently Asked QuestionsDiscontinuedHOW TO BUYRecommended SystemsA Beginner\\u2019s Guide to Good AudioWhat Is High End Audio ?What Is High End DAC ?Amp Comparison & Sonic CharacteristicAmp Design & NuPrime\\u2019s AdvantagesMQA & DACsWireless Audio Technology GuideCOMMUNITY & NEWSFacebook & InstagramCustomer BlogCommunity ForumTrade Shows & NewsWHERE TO BUYCONTACT & SUPPORTContact & SupportHelp DeskWarranty RegistrationFrequently Asked QuestionsSearch for:Search\\u2026Home \/ Amplifier & PreampAMG STAEUR 1,695.00The AMG STA comprises of several state-of-the-art innovations in power amp design. Its class-leading features include 1M Ohm input impedance, high instantaneous current for power delivery, 700kHz switching frequency, and Single-Ended Non-Negative Class A module coupled with Double Feedback Class D module for 300W mono amp power.Category: Amplifier & PreampTag: AMG Series DESCRIPTIONSPECSFAQ & FORUMREVIEWDOWNLOADThe AMG series front panel embodies its spirit. It is milled from a 15mm harden aerospace aluminum alloy using a four-axis CNC machine with a diamond cutter through a 48 steps process. Design elements such as the 3D \\u201cfloating\\u201d logo, the curved surface around the front panel switch, and diamond-cut edge bring the quality of ultra-high-end audio products to the affordable range of the AMG series.TechnologyAMG STA PCB integrates ground wire shielding to isolate external interference. The 300 Mhz bandwidth JFET provides ultra-high input impedance and wide-band fast response. The dynamics of the design and the single-ended Class A circuit enriches the natural second harmonic.This design allows the most delicate details in the audio signal to carry through the chain. The level of transparency in sound reproduction is genuinely astonishing in this class of equipment, with a deft in creating a highly detailed sonic imagery.The AMG-STA uses the \\u201cSingle-Ended, Non-Negative Feedback\\u201d Class-A module partners with a new \\u201cDouble feedback\\u201d Class D circuitry. The Class D oscillating frequency has increased to 700kHz, which is 1.4 times that of the STA-9.Power CircuitThe power supply uses a 380W special winding power transformer, which has 30% more peak power output of a similar volume transformer.The AC power input from the Inlet Connector to the power transformer utilizes a high current welding line to provide maximum power transmission.Besides, high-frequency 3rd-order AC power filter reduces external noise.A 20A lock wire terminal block connects the transformer to the motherboard, in parallel with two10A peak current rectifiers.The main current path, adopting a large-capacity current design, uses a low-impedance copper plate to maximize power delivery to the amplifier circuits.How did AMG STA mono achieve better sonic characteristic, in addition to more power than AMG STA stereo ?The standard method for bridging a stereo amp into mono employs a series of op amps (OPA) in order to invert the input signals to one of the stereo amp, thereby creating an opposite phase, which can then be combined to increase power. Conversely, the AMG STA\\u2019s innovative bridging circuit utilises a design we call Single-Ended Direct-Inject Bridge Technology, in which the mono mode, in addition to acquiring more than double the power, sounds livelier and more dynamic.Listening ImpressionWith improvements to every area, the bar has been raised for what is achievable with audio performance in small form factor.The AMG STA has a flavor of its own, so it is hard to compare it with the Evolution One, which derives some of its design from or the similarly priced ST-10. AMG STA sounded smooth and relaxing. Detail, resolution, dynamics, and speed are in the ST-10 ballpark, yet the sound is quite different.Drawing comparison with the Evolution One, they shared a trait of ease in reproducing the details of the recording comes afore. However, AMG STA does things differently. While the Evolution One has that inviting warmth, the AMG STA wants to allure the listener. Hence, instead of glitz and glamor, which pulls you in quickly into the performance, the AMG STA has a demeanor that slowly brings you into the music.Tonal qualities of the AMG STA leans toward being full and rich, so instruments and vocals seem to gain extra body, weight, and harmonic richness. It may not be the most accurate reproduction but does make Jazz and Vocal pieces highly addictive. It may take away the raw edge of Rock and Electronic music and sounds less exciting for some.The sound stage has an attractive characteristic. A linear presentation is like having floodlights shining on all the performers such that everyone can be seen equally well. The AMG STA, however, has more of a spotlighting effect, where performers are focused on getting your attention.It is tough to put the sound of the AMG STA into measurable attributes as the presentation is quite different from the other series. You\\u2019ll need to try it and hear for yourself.RELATED PRODUCTSABOUT US NUPRIME-X NEWSLETTER PRIVACY POLICYCopyright 2021 \\u00a9 Nuprime Audio, Inc. --- brand managed by Nuoem Pte. Ltd.\",\"breadcrumb\":{\"@id\":\"https:\/\/intek-hifi.com\/nuprime-amg-sta-power-amplifier-and-amg-pra-preamplifier-tas-review\/#breadcrumb\"},\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\/\/intek-hifi.com\/nuprime-amg-sta-power-amplifier-and-amg-pra-preamplifier-tas-review\/\"]}]},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\/\/intek-hifi.com\/nuprime-amg-sta-power-amplifier-and-amg-pra-preamplifier-tas-review\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\/\/intek-hifi.com\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"NUPRIME AMG STA Power Amplifier and AMG PRA Preamplifier > TAS review\"}]},{\"@type\":\"Person\",\"@id\":\"https:\/\/intek-hifi.com\/#\/schema\/person\/02fa1742be92272c2fe50f2579f320e7\",\"name\":\"darko\",\"image\":{\"@type\":\"ImageObject\",\"@id\":\"https:\/\/intek-hifi.com\/#personlogo\",\"inLanguage\":\"en-US\",\"url\":\"https:\/\/secure.gravatar.com\/avatar\/d3b6149fb1fb06b36083b7009dbff0af?s=96&d=mm&r=g\",\"contentUrl\":\"https:\/\/secure.gravatar.com\/avatar\/d3b6149fb1fb06b36083b7009dbff0af?s=96&d=mm&r=g\",\"caption\":\"darko\"},\"url\":\"https:\/\/intek-hifi.com\/en\/author\/darko\/\"}]}<\/script>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"NUPRIME AMG STA Power Amplifier and AMG PRA Preamplifier > TAS review - INTEK HI-FI","description":"I don\u2019t have a ton of experience with NuPrime, but here\u2019s a quick, high-level history lesson: The company was founded back in 2014 by Jason Lim, the former CEO of NuForce, and it specializes in boutique Class D amps, media streamers, and many other products. I was very excited to get a nearly complete system of its AMG STA power amplifier and AMG PRA preamp. The amp and preamp combination have the same form factor and were clearly designed to work in tandem. While I\u2019m a fan of mixing and matching equipment from a wide range of manufacturers, there\u2019s something special about listening to the products from a single line, and getting a sense of how they work in tandem.Diving in, the NuPrime AMG STA ($1695) is a sleek, compact Class D power amplifier with a Class A preamp stage and linear power supply. The chassis is simple, with only a metal switch on the front for power, a small white LED indicator, and the NuPrime logo. My review sample came in dark gray, and looked good in my relatively tight equipment rack. As power amps go, the AMG STA never gets overly hot\u2014likely a product of its very efficient Class D output module\u2014though it does get somewhat warm. The back is relatively cramped, and it took a little contortion to get everything hooked up, but that didn\u2019t matter much once it was plugged it and powered on. The power amp supplies a solid 130Wpc into 8 ohms in stereo mode and 300Wpc into 8 ohms in mono mode. That\u2019s one of my favorite features of the PRA\u2014its ability to work as either a single stereo amplifier or in tandem with a second STA as part of a monoblock setup.The AMG PRA ($1795) looks almost exactly like the AMG STA power amp\u2014sorry for the vaguely confusing names\u2014but with two knobs and an LED indicator for channel and volume setting on the front panel. The left knob controls the unit\u2019s loudness compensation feature, which is something I\u2019ll talk about in a second. The right knob plays a bigger role\u2014push and hold for standby mode, push briefly to select inputs, and turn to adjust volume. Two toggles on the front switch between high and low gain and between normal and inverted phase. On the back, the PRA includes one set of balanced inputs and three unbalanced RCAs, along with a balanced and unbalanced out. The remote is heavy enough to break a toe if dropped and seems to be milled from solid aluminum; it performed all the functions I could possibly want\u2014from power to volume control to input switching. Overall, the PRA\u2019s design is simple, but attractive and effective.Before I dive into listening, it\u2019s time to look at the \u201cActive Low Frequency and Harmonic Gain\u201d control feature. To put it very simply, this knob is somewhat like Ye Olde Loudness switch of yore. When turned on it very noticeably boosts bass, without increasing the overall volume. It is an interesting EQ effect, and definitely achieves NuPrime\u2019s stated goal of giving smaller speakers a bit more natural low end. It worked well with my Wharfedale 225s, and actually sounded fairly nice with my Omen Dirty Weekend on its lowest setting. However, through the Polk L600 (review forthcoming), the knob made the bass a little too flabby, which makes sense. (The L600 have a very deep low end, and compensating made the bass a little too intense.) Each setting on the knob is a different EQ curve, and it may be worth experimenting with them to find the one that works best in your setup. For the following review, I kept the knob turned to the left, which turns the feature off. First up, I plugged in a single AMG STA amplifier with the AMG PRA preamp. (I was sent two STAs by NuPrime, so I did half my listening with one, and half with the dual-mono setup.) The single STA was more than enough to power my Zu Omen Dirty Weekends, and made my copy of the recent Ray Charles vinyl reissue Genius + Soul = Jazz sing and scream and shout. Lows were suitably solid, and the midrange really shone with an extremely pleasant smoothness. I never felt as though the AMG STA lagged behind or ran out of headroom powering the Zu DWs, even on this very dynamic recording. Ray Charles sounded fantastic, and his organ really grooved in tight and exciting lines. After trying the Zu DWs, I gave the Polk L600s a shot in the single AMG STA configuration. The Polk speakers are much more difficult to drive than the Zu DWs, but the STA still had plenty of space and headroom to blast through those fiery Ray Charles licks. I decided to try the Analogue Productions vinyl reissue of the RCA release Witches\u2019 Brew to see how it handled something dynamic that might stress its capabilities a bit. Even at its loudest, biggest moments, when the orchestra swells and cymbals crash, I never felt as though the AMG STA was lagging behind, even powering the difficult L600s. The low end was deep and slammed\u2014not quite razor-sharp but not flabby, either. The midrange had an ease to it, a nice, relaxed presentation. Horns were sharp and evenly spaced, and their upper registers had a bit of sparkle. Of the two speaker pairs I tried out, I\u2019d say the single AMG STA worked best with the Zu DWs, likely because they\u2019re easier to drive, but also because they share a similar sound profile\u2014relaxed, with a delightful midrange, a decently solid lower end, and a shimmery treble.I switched over to the dual-mono setup next, which gave me a solid 300Wpc into 8 ohms. That\u2019s way more than enough for the Zu Omen DWs, since they\u2019re easy to drive, but I liked the limitless-feeling headroom that the dual-mono combination bought me. I didn\u2019t find it necessarily sounded better, just more centered and solid, with no straining or restraint. Where this dual-mono configuration really worked was with the Polk L600s, the more difficult pair of speakers to drive. The AMG STA retained its signature relaxed and easy sound, but with that much power on tap really opened up the full potential of the Polks. The backgrounds were shockingly black, and it almost felt as if the AMG PRA preamp was nearly transparent, if you\u2019ll forgive a reviewing clich\u00e9. That deep noise floor allowed the music to shine with a crispness and dynamism that I absolutely loved.Sticking with the dual-mono setup and the L600s, I put on the Tone Poets vinyl reissue of My Point of View by Herbie Hancock. The tune \u201cKing Cobra\u201d opens the B-side, and it features Tony Williams at only 17 years old showing off all his incredible potential, with dancing cymbals that really sparkled through the STA\/PRA combo. Williams\u2019 fills sounded exuberant and rhythmically complex, and the system never compromised or slowed down his fascinating drumming. In the midrange, the piano and horns were smooth and silky with a hint of nice, heavy warmth down in their lower regions. Hancock\u2019s solo was quick and slithering, like the song\u2019s namesake, and each note was clearly delineated. Attacks and decays were on point, which added to the whole rhythmic picture building throughout the song. When the horns massed for the theme, each instrument remained wholly itself and focused, creating a wide sense of soundstage. The STA\/PRA dual-mono combo worked very well with the L600s, since the speakers have a very solid and deep lower end, and the amp\/preamp shines in the lower registers. It was that deep heft that really brought a difficult song like \u201cKing Cobra\u201d to life, and leant the entire ensemble a massive sound. Next up, I listened to Iceage\u2019s most recent album Seek Shelter, streamed via Tidal. On the opening track, \u201cShelter Song,\u201d the fuzzy guitar had a solid growl, while the deep kick drum slammed. The choir added depth and texture without ever straying into chaos. There was a surprisingly strong sense of place and positioning. Despite the sheer number of sounds occurring at the same time, I could still pinpoint each voice and instrument, and I think the monoblocks\u2019 massive amount of headroom went a long way to allowing the weight of the song to shine through. Later on the record, on the hard-rocking banger \u201cSaint Cecilia,\u201d the heavy guitars and screaming solos and choral shouts built into really epic, room-encompassing crescendos. The low end felt solid and intense, while the upper range of the twanging guitar had genuine dazzle. Overall, I felt the PRA\/STA combo played very nicely with some serious rock and roll.I really enjoyed the NuPrime AMG PRA preamplifier and the AMG STA power amplifier. I didn\u2019t waste any time hand-wringing over Class D, and barely even mention it in my review\u2014for good reason. The STA\/PRA combination sounded great, with a heavy low end, a relaxed and pleasant midrange, and just enough sparkle in the upper end to make cymbals shimmer. The interesting loudness function on the PRA and the very nicely made remote control were the kind of simple but useful upgrades over a standard preamp that made this combination feel premium. For many folks, I suspect a single STA will provide enough power, but for those who have more difficult-to-drive speakers, or those who want a massive amount of power on tap and ready to go, the monoblock setup is fantastic. This is a system worth trying and comes highly recommended.Specs & PricingAMG PRA PreamplifierFrequency response: 10Hz to 200kHz; +-0 to -0.1dBTHD: 0.008 %Input impedance: 1M ohm @10Hz\u2013200kHzS\/N: 95dBLoudness compensation: 2.2dB (125Hz)\/4.5dB (100Hz)\/5.3dB (75Hz)Gain: 3.2(High)\/2.1(Low)Inputs: 3x RCA, 1x balancedDimensions: 9.25\u2033 x 11.8\u2033 x 2.1\u2033Weight: 5.5 lbs.Price: $1795AMG STA Power AmplifierStereo power: 2x 130W at 8 ohms & 2x 200W at 4 ohmsMono power: 300W at 8 ohms & 320W at 4 ohmsPeak current: 10A\/15AGain: 26 (stereo) & 52 (mono)SNR: 100dB at 10WTHD+N: 0.006Frequency response: 10Hz\u201350kHz \u00b10.2dB at 8 ohmsInput impedance: 1M ohmSensitivity: 1.2Vrms stereo; 0.95Vrms monoDimensions: 9.25\u2033 x 11.3\u2033 x 2.1\u2033Weight: 8.8 lbs.Price: $1695 Skip to contentNuPrime AudioPRODUCTSProduct CategoriesProduct ListingShowroomsFrequently Asked QuestionsDiscontinuedHOW TO BUYRecommended SystemsA Beginner\u2019s Guide to Good AudioWhat Is High End Audio ?What Is High End DAC ?Amp Comparison & Sonic CharacteristicAmp Design & NuPrime\u2019s AdvantagesMQA & DACsWireless Audio Technology GuideCOMMUNITY & NEWSFacebook & InstagramCustomer BlogCommunity ForumTrade Shows & NewsWHERE TO BUYCONTACT & SUPPORTContact & SupportHelp DeskWarranty RegistrationFrequently Asked QuestionsSearch for:Search\u2026Home \/ Amplifier & PreampAMG PRAEUR 1,795.00The AMG PRA went beyond being a transparent preamp with 1M Ohm input impedance and the best analog source inputs. A user-selectable 4 stage \u201cActive Low Frequency and Harmonic Gain\u201d control gave it distinctive characteristics to enhance the speaker performance, a world-first in preamp design.Category: Amplifier & PreampTag: High-End Series DESCRIPTIONSPECSLOUDNESSREVIEWDOWNLOADThe AMG series front panel embodies its spirit. It is milled from a 15mm harden aerospace aluminum alloy using a four-axis CNC machine with a diamond cutter through a 48 steps process. Design elements such as the 3D \u201cfloating\u201d logo, the curved surface around the front panel switch, and diamond-cut edge bring the quality of ultra-high-end audio products to the affordable range of the AMG series.The design goal for AMG PRA was to deliver a transparent sounding analog preamp with its distinctive characteristics. Several new design concepts were developed and used in the AMG-PRE besides 1M\u03a9 input impedance to achieve the best analog inputs.Users of smallish speakers would often detect a distinct drop in bass response with some audio tracks. Instead of a simple \u201cBass Boost\u201d function that lifts a targeted low-frequency band, a user-selectable 4 stage \u201cActive Low Frequency and Harmonic Gain\u201d control compensates for the lack of bass presence. It achieves some bass extension and a more natural roll-off.Additional features such as the 2 stage gain control and invertible phase control increase the compatibility of the AMG-PRA with other power amplifiers.Technical DetailsThe layout of the AMG-PRA takes excellent care in isolating the sensitive audio signals from the power circuitry. The power circuitry comprising of a star topology power and ground layers is built on one board while a separate board houses the pre-amplification circuit. An isolation layer separates these two boards, which further minimizes interference. The effect is a highly transparent sound that is natural and not over etched.MUSES72320 Digital Volume ControlONE MEGA ultra-wide bandwidth low noise JFET, single-ended Class A input design and MUSES8920 Op-amp produce harmonics similar to vacuum tube amps, which has a \u201cwarm, airy and velvety\u201d sound characteristic.Non-feedback low-frequency domain Frequency Harmonic Modulation circuit provides minimum phase distortion and tone error.Inputs and outputs are fully balanced design.Front Panel SettingsLeft Toggle Switch: Output GainUpwards : High GainDownwards : Low GainRight Toggle Switch: Output PhaseUpwards : Phase InvertDownwards : Phase NormalLeft knob: Loudness CompensationTurn the knob to switch between Loudness CompensationRight Knob: Power and Input Selector and VolumesBriefly press for 3 sec to On\/Off standby modeBrief press to Input SelectorTurn the knob to adjust volumeAMG Remote ControlRELATED PRODUCTSAMPLIFIER & PREAMPAMG STAEUR 1,695.00The AMG STA comprises of several state-of-the-art innovations in power amp design. Its class-leading features include 1M Ohm input impedance, high instantaneous current for power delivery, 700kHz switching frequency, and Single-Ended Non-Negative Class A module coupled with Double Feedback Class D module for 300W mono amp power.ABOUT US NUPRIME-X NEWSLETTER PRIVACY POLICYCopyright 2021 \u00a9 Nuprime Audio, Inc. --- brand managed by Nuoem Pte. Ltd. Skip to contentBEYOND ORDINARYAbout UsNuPrime-XNewsletterPrivacy PolicyNuPrime AudioPRODUCTSProduct CategoriesProduct ListingShowroomsFrequently Asked QuestionsDiscontinuedHOW TO BUYRecommended SystemsA Beginner\u2019s Guide to Good AudioWhat Is High End Audio ?What Is High End DAC ?Amp Comparison & Sonic CharacteristicAmp Design & NuPrime\u2019s AdvantagesMQA & DACsWireless Audio Technology GuideCOMMUNITY & NEWSFacebook & InstagramCustomer BlogCommunity ForumTrade Shows & NewsWHERE TO BUYCONTACT & SUPPORTContact & SupportHelp DeskWarranty RegistrationFrequently Asked QuestionsSearch for:Search\u2026Home \/ Amplifier & PreampAMG STAEUR 1,695.00The AMG STA comprises of several state-of-the-art innovations in power amp design. Its class-leading features include 1M Ohm input impedance, high instantaneous current for power delivery, 700kHz switching frequency, and Single-Ended Non-Negative Class A module coupled with Double Feedback Class D module for 300W mono amp power.Category: Amplifier & PreampTag: AMG Series DESCRIPTIONSPECSFAQ & FORUMREVIEWDOWNLOADThe AMG series front panel embodies its spirit. It is milled from a 15mm harden aerospace aluminum alloy using a four-axis CNC machine with a diamond cutter through a 48 steps process. Design elements such as the 3D \u201cfloating\u201d logo, the curved surface around the front panel switch, and diamond-cut edge bring the quality of ultra-high-end audio products to the affordable range of the AMG series.TechnologyAMG STA PCB integrates ground wire shielding to isolate external interference. The 300 Mhz bandwidth JFET provides ultra-high input impedance and wide-band fast response. The dynamics of the design and the single-ended Class A circuit enriches the natural second harmonic.This design allows the most delicate details in the audio signal to carry through the chain. The level of transparency in sound reproduction is genuinely astonishing in this class of equipment, with a deft in creating a highly detailed sonic imagery.The AMG-STA uses the \u201cSingle-Ended, Non-Negative Feedback\u201d Class-A module partners with a new \u201cDouble feedback\u201d Class D circuitry. The Class D oscillating frequency has increased to 700kHz, which is 1.4 times that of the STA-9.Power CircuitThe power supply uses a 380W special winding power transformer, which has 30% more peak power output of a similar volume transformer.The AC power input from the Inlet Connector to the power transformer utilizes a high current welding line to provide maximum power transmission.Besides, high-frequency 3rd-order AC power filter reduces external noise.A 20A lock wire terminal block connects the transformer to the motherboard, in parallel with two10A peak current rectifiers.The main current path, adopting a large-capacity current design, uses a low-impedance copper plate to maximize power delivery to the amplifier circuits.How did AMG STA mono achieve better sonic characteristic, in addition to more power than AMG STA stereo ?The standard method for bridging a stereo amp into mono employs a series of op amps (OPA) in order to invert the input signals to one of the stereo amp, thereby creating an opposite phase, which can then be combined to increase power. Conversely, the AMG STA\u2019s innovative bridging circuit utilises a design we call Single-Ended Direct-Inject Bridge Technology, in which the mono mode, in addition to acquiring more than double the power, sounds livelier and more dynamic.Listening ImpressionWith improvements to every area, the bar has been raised for what is achievable with audio performance in small form factor.The AMG STA has a flavor of its own, so it is hard to compare it with the Evolution One, which derives some of its design from or the similarly priced ST-10. AMG STA sounded smooth and relaxing. Detail, resolution, dynamics, and speed are in the ST-10 ballpark, yet the sound is quite different.Drawing comparison with the Evolution One, they shared a trait of ease in reproducing the details of the recording comes afore. However, AMG STA does things differently. While the Evolution One has that inviting warmth, the AMG STA wants to allure the listener. Hence, instead of glitz and glamor, which pulls you in quickly into the performance, the AMG STA has a demeanor that slowly brings you into the music.Tonal qualities of the AMG STA leans toward being full and rich, so instruments and vocals seem to gain extra body, weight, and harmonic richness. It may not be the most accurate reproduction but does make Jazz and Vocal pieces highly addictive. It may take away the raw edge of Rock and Electronic music and sounds less exciting for some.The sound stage has an attractive characteristic. A linear presentation is like having floodlights shining on all the performers such that everyone can be seen equally well. The AMG STA, however, has more of a spotlighting effect, where performers are focused on getting your attention.It is tough to put the sound of the AMG STA into measurable attributes as the presentation is quite different from the other series. You\u2019ll need to try it and hear for yourself.RELATED PRODUCTSABOUT US NUPRIME-X NEWSLETTER PRIVACY POLICYCopyright 2021 \u00a9 Nuprime Audio, Inc. --- brand managed by Nuoem Pte. Ltd.","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/intek-hifi.com\/en\/nuprime-amg-sta-power-amplifier-and-amg-pra-preamplifier-tas-review\/","og_locale":"en_US","og_type":"article","og_title":"NUPRIME AMG STA Power Amplifier and AMG PRA Preamplifier > TAS review - INTEK HI-FI","og_description":"I don\u2019t have a ton of experience with NuPrime, but here\u2019s a quick, high-level history lesson: The company was founded back in 2014 by Jason Lim, the former CEO of NuForce, and it specializes in boutique Class D amps, media streamers, and many other products. I was very excited to get a nearly complete system of its AMG STA power amplifier and AMG PRA preamp. The amp and preamp combination have the same form factor and were clearly designed to work in tandem. While I\u2019m a fan of mixing and matching equipment from a wide range of manufacturers, there\u2019s something special about listening to the products from a single line, and getting a sense of how they work in tandem.Diving in, the NuPrime AMG STA ($1695) is a sleek, compact Class D power amplifier with a Class A preamp stage and linear power supply. The chassis is simple, with only a metal switch on the front for power, a small white LED indicator, and the NuPrime logo. My review sample came in dark gray, and looked good in my relatively tight equipment rack. As power amps go, the AMG STA never gets overly hot\u2014likely a product of its very efficient Class D output module\u2014though it does get somewhat warm. The back is relatively cramped, and it took a little contortion to get everything hooked up, but that didn\u2019t matter much once it was plugged it and powered on. The power amp supplies a solid 130Wpc into 8 ohms in stereo mode and 300Wpc into 8 ohms in mono mode. That\u2019s one of my favorite features of the PRA\u2014its ability to work as either a single stereo amplifier or in tandem with a second STA as part of a monoblock setup.The AMG PRA ($1795) looks almost exactly like the AMG STA power amp\u2014sorry for the vaguely confusing names\u2014but with two knobs and an LED indicator for channel and volume setting on the front panel. The left knob controls the unit\u2019s loudness compensation feature, which is something I\u2019ll talk about in a second. The right knob plays a bigger role\u2014push and hold for standby mode, push briefly to select inputs, and turn to adjust volume. Two toggles on the front switch between high and low gain and between normal and inverted phase. On the back, the PRA includes one set of balanced inputs and three unbalanced RCAs, along with a balanced and unbalanced out. The remote is heavy enough to break a toe if dropped and seems to be milled from solid aluminum; it performed all the functions I could possibly want\u2014from power to volume control to input switching. Overall, the PRA\u2019s design is simple, but attractive and effective.Before I dive into listening, it\u2019s time to look at the \u201cActive Low Frequency and Harmonic Gain\u201d control feature. To put it very simply, this knob is somewhat like Ye Olde Loudness switch of yore. When turned on it very noticeably boosts bass, without increasing the overall volume. It is an interesting EQ effect, and definitely achieves NuPrime\u2019s stated goal of giving smaller speakers a bit more natural low end. It worked well with my Wharfedale 225s, and actually sounded fairly nice with my Omen Dirty Weekend on its lowest setting. However, through the Polk L600 (review forthcoming), the knob made the bass a little too flabby, which makes sense. (The L600 have a very deep low end, and compensating made the bass a little too intense.) Each setting on the knob is a different EQ curve, and it may be worth experimenting with them to find the one that works best in your setup. For the following review, I kept the knob turned to the left, which turns the feature off. First up, I plugged in a single AMG STA amplifier with the AMG PRA preamp. (I was sent two STAs by NuPrime, so I did half my listening with one, and half with the dual-mono setup.) The single STA was more than enough to power my Zu Omen Dirty Weekends, and made my copy of the recent Ray Charles vinyl reissue Genius + Soul = Jazz sing and scream and shout. Lows were suitably solid, and the midrange really shone with an extremely pleasant smoothness. I never felt as though the AMG STA lagged behind or ran out of headroom powering the Zu DWs, even on this very dynamic recording. Ray Charles sounded fantastic, and his organ really grooved in tight and exciting lines. After trying the Zu DWs, I gave the Polk L600s a shot in the single AMG STA configuration. The Polk speakers are much more difficult to drive than the Zu DWs, but the STA still had plenty of space and headroom to blast through those fiery Ray Charles licks. I decided to try the Analogue Productions vinyl reissue of the RCA release Witches\u2019 Brew to see how it handled something dynamic that might stress its capabilities a bit. Even at its loudest, biggest moments, when the orchestra swells and cymbals crash, I never felt as though the AMG STA was lagging behind, even powering the difficult L600s. The low end was deep and slammed\u2014not quite razor-sharp but not flabby, either. The midrange had an ease to it, a nice, relaxed presentation. Horns were sharp and evenly spaced, and their upper registers had a bit of sparkle. Of the two speaker pairs I tried out, I\u2019d say the single AMG STA worked best with the Zu DWs, likely because they\u2019re easier to drive, but also because they share a similar sound profile\u2014relaxed, with a delightful midrange, a decently solid lower end, and a shimmery treble.I switched over to the dual-mono setup next, which gave me a solid 300Wpc into 8 ohms. That\u2019s way more than enough for the Zu Omen DWs, since they\u2019re easy to drive, but I liked the limitless-feeling headroom that the dual-mono combination bought me. I didn\u2019t find it necessarily sounded better, just more centered and solid, with no straining or restraint. Where this dual-mono configuration really worked was with the Polk L600s, the more difficult pair of speakers to drive. The AMG STA retained its signature relaxed and easy sound, but with that much power on tap really opened up the full potential of the Polks. The backgrounds were shockingly black, and it almost felt as if the AMG PRA preamp was nearly transparent, if you\u2019ll forgive a reviewing clich\u00e9. That deep noise floor allowed the music to shine with a crispness and dynamism that I absolutely loved.Sticking with the dual-mono setup and the L600s, I put on the Tone Poets vinyl reissue of My Point of View by Herbie Hancock. The tune \u201cKing Cobra\u201d opens the B-side, and it features Tony Williams at only 17 years old showing off all his incredible potential, with dancing cymbals that really sparkled through the STA\/PRA combo. Williams\u2019 fills sounded exuberant and rhythmically complex, and the system never compromised or slowed down his fascinating drumming. In the midrange, the piano and horns were smooth and silky with a hint of nice, heavy warmth down in their lower regions. Hancock\u2019s solo was quick and slithering, like the song\u2019s namesake, and each note was clearly delineated. Attacks and decays were on point, which added to the whole rhythmic picture building throughout the song. When the horns massed for the theme, each instrument remained wholly itself and focused, creating a wide sense of soundstage. The STA\/PRA dual-mono combo worked very well with the L600s, since the speakers have a very solid and deep lower end, and the amp\/preamp shines in the lower registers. It was that deep heft that really brought a difficult song like \u201cKing Cobra\u201d to life, and leant the entire ensemble a massive sound. Next up, I listened to Iceage\u2019s most recent album Seek Shelter, streamed via Tidal. On the opening track, \u201cShelter Song,\u201d the fuzzy guitar had a solid growl, while the deep kick drum slammed. The choir added depth and texture without ever straying into chaos. There was a surprisingly strong sense of place and positioning. Despite the sheer number of sounds occurring at the same time, I could still pinpoint each voice and instrument, and I think the monoblocks\u2019 massive amount of headroom went a long way to allowing the weight of the song to shine through. Later on the record, on the hard-rocking banger \u201cSaint Cecilia,\u201d the heavy guitars and screaming solos and choral shouts built into really epic, room-encompassing crescendos. The low end felt solid and intense, while the upper range of the twanging guitar had genuine dazzle. Overall, I felt the PRA\/STA combo played very nicely with some serious rock and roll.I really enjoyed the NuPrime AMG PRA preamplifier and the AMG STA power amplifier. I didn\u2019t waste any time hand-wringing over Class D, and barely even mention it in my review\u2014for good reason. The STA\/PRA combination sounded great, with a heavy low end, a relaxed and pleasant midrange, and just enough sparkle in the upper end to make cymbals shimmer. The interesting loudness function on the PRA and the very nicely made remote control were the kind of simple but useful upgrades over a standard preamp that made this combination feel premium. For many folks, I suspect a single STA will provide enough power, but for those who have more difficult-to-drive speakers, or those who want a massive amount of power on tap and ready to go, the monoblock setup is fantastic. This is a system worth trying and comes highly recommended.Specs & PricingAMG PRA PreamplifierFrequency response: 10Hz to 200kHz; +-0 to -0.1dBTHD: 0.008 %Input impedance: 1M ohm @10Hz\u2013200kHzS\/N: 95dBLoudness compensation: 2.2dB (125Hz)\/4.5dB (100Hz)\/5.3dB (75Hz)Gain: 3.2(High)\/2.1(Low)Inputs: 3x RCA, 1x balancedDimensions: 9.25\u2033 x 11.8\u2033 x 2.1\u2033Weight: 5.5 lbs.Price: $1795AMG STA Power AmplifierStereo power: 2x 130W at 8 ohms & 2x 200W at 4 ohmsMono power: 300W at 8 ohms & 320W at 4 ohmsPeak current: 10A\/15AGain: 26 (stereo) & 52 (mono)SNR: 100dB at 10WTHD+N: 0.006Frequency response: 10Hz\u201350kHz \u00b10.2dB at 8 ohmsInput impedance: 1M ohmSensitivity: 1.2Vrms stereo; 0.95Vrms monoDimensions: 9.25\u2033 x 11.3\u2033 x 2.1\u2033Weight: 8.8 lbs.Price: $1695 Skip to contentNuPrime AudioPRODUCTSProduct CategoriesProduct ListingShowroomsFrequently Asked QuestionsDiscontinuedHOW TO BUYRecommended SystemsA Beginner\u2019s Guide to Good AudioWhat Is High End Audio ?What Is High End DAC ?Amp Comparison & Sonic CharacteristicAmp Design & NuPrime\u2019s AdvantagesMQA & DACsWireless Audio Technology GuideCOMMUNITY & NEWSFacebook & InstagramCustomer BlogCommunity ForumTrade Shows & NewsWHERE TO BUYCONTACT & SUPPORTContact & SupportHelp DeskWarranty RegistrationFrequently Asked QuestionsSearch for:Search\u2026Home \/ Amplifier & PreampAMG PRAEUR 1,795.00The AMG PRA went beyond being a transparent preamp with 1M Ohm input impedance and the best analog source inputs. A user-selectable 4 stage \u201cActive Low Frequency and Harmonic Gain\u201d control gave it distinctive characteristics to enhance the speaker performance, a world-first in preamp design.Category: Amplifier & PreampTag: High-End Series DESCRIPTIONSPECSLOUDNESSREVIEWDOWNLOADThe AMG series front panel embodies its spirit. It is milled from a 15mm harden aerospace aluminum alloy using a four-axis CNC machine with a diamond cutter through a 48 steps process. Design elements such as the 3D \u201cfloating\u201d logo, the curved surface around the front panel switch, and diamond-cut edge bring the quality of ultra-high-end audio products to the affordable range of the AMG series.The design goal for AMG PRA was to deliver a transparent sounding analog preamp with its distinctive characteristics. Several new design concepts were developed and used in the AMG-PRE besides 1M\u03a9 input impedance to achieve the best analog inputs.Users of smallish speakers would often detect a distinct drop in bass response with some audio tracks. Instead of a simple \u201cBass Boost\u201d function that lifts a targeted low-frequency band, a user-selectable 4 stage \u201cActive Low Frequency and Harmonic Gain\u201d control compensates for the lack of bass presence. It achieves some bass extension and a more natural roll-off.Additional features such as the 2 stage gain control and invertible phase control increase the compatibility of the AMG-PRA with other power amplifiers.Technical DetailsThe layout of the AMG-PRA takes excellent care in isolating the sensitive audio signals from the power circuitry. The power circuitry comprising of a star topology power and ground layers is built on one board while a separate board houses the pre-amplification circuit. An isolation layer separates these two boards, which further minimizes interference. The effect is a highly transparent sound that is natural and not over etched.MUSES72320 Digital Volume ControlONE MEGA ultra-wide bandwidth low noise JFET, single-ended Class A input design and MUSES8920 Op-amp produce harmonics similar to vacuum tube amps, which has a \u201cwarm, airy and velvety\u201d sound characteristic.Non-feedback low-frequency domain Frequency Harmonic Modulation circuit provides minimum phase distortion and tone error.Inputs and outputs are fully balanced design.Front Panel SettingsLeft Toggle Switch: Output GainUpwards : High GainDownwards : Low GainRight Toggle Switch: Output PhaseUpwards : Phase InvertDownwards : Phase NormalLeft knob: Loudness CompensationTurn the knob to switch between Loudness CompensationRight Knob: Power and Input Selector and VolumesBriefly press for 3 sec to On\/Off standby modeBrief press to Input SelectorTurn the knob to adjust volumeAMG Remote ControlRELATED PRODUCTSAMPLIFIER & PREAMPAMG STAEUR 1,695.00The AMG STA comprises of several state-of-the-art innovations in power amp design. Its class-leading features include 1M Ohm input impedance, high instantaneous current for power delivery, 700kHz switching frequency, and Single-Ended Non-Negative Class A module coupled with Double Feedback Class D module for 300W mono amp power.ABOUT US NUPRIME-X NEWSLETTER PRIVACY POLICYCopyright 2021 \u00a9 Nuprime Audio, Inc. --- brand managed by Nuoem Pte. Ltd. Skip to contentBEYOND ORDINARYAbout UsNuPrime-XNewsletterPrivacy PolicyNuPrime AudioPRODUCTSProduct CategoriesProduct ListingShowroomsFrequently Asked QuestionsDiscontinuedHOW TO BUYRecommended SystemsA Beginner\u2019s Guide to Good AudioWhat Is High End Audio ?What Is High End DAC ?Amp Comparison & Sonic CharacteristicAmp Design & NuPrime\u2019s AdvantagesMQA & DACsWireless Audio Technology GuideCOMMUNITY & NEWSFacebook & InstagramCustomer BlogCommunity ForumTrade Shows & NewsWHERE TO BUYCONTACT & SUPPORTContact & SupportHelp DeskWarranty RegistrationFrequently Asked QuestionsSearch for:Search\u2026Home \/ Amplifier & PreampAMG STAEUR 1,695.00The AMG STA comprises of several state-of-the-art innovations in power amp design. Its class-leading features include 1M Ohm input impedance, high instantaneous current for power delivery, 700kHz switching frequency, and Single-Ended Non-Negative Class A module coupled with Double Feedback Class D module for 300W mono amp power.Category: Amplifier & PreampTag: AMG Series DESCRIPTIONSPECSFAQ & FORUMREVIEWDOWNLOADThe AMG series front panel embodies its spirit. It is milled from a 15mm harden aerospace aluminum alloy using a four-axis CNC machine with a diamond cutter through a 48 steps process. Design elements such as the 3D \u201cfloating\u201d logo, the curved surface around the front panel switch, and diamond-cut edge bring the quality of ultra-high-end audio products to the affordable range of the AMG series.TechnologyAMG STA PCB integrates ground wire shielding to isolate external interference. The 300 Mhz bandwidth JFET provides ultra-high input impedance and wide-band fast response. The dynamics of the design and the single-ended Class A circuit enriches the natural second harmonic.This design allows the most delicate details in the audio signal to carry through the chain. The level of transparency in sound reproduction is genuinely astonishing in this class of equipment, with a deft in creating a highly detailed sonic imagery.The AMG-STA uses the \u201cSingle-Ended, Non-Negative Feedback\u201d Class-A module partners with a new \u201cDouble feedback\u201d Class D circuitry. The Class D oscillating frequency has increased to 700kHz, which is 1.4 times that of the STA-9.Power CircuitThe power supply uses a 380W special winding power transformer, which has 30% more peak power output of a similar volume transformer.The AC power input from the Inlet Connector to the power transformer utilizes a high current welding line to provide maximum power transmission.Besides, high-frequency 3rd-order AC power filter reduces external noise.A 20A lock wire terminal block connects the transformer to the motherboard, in parallel with two10A peak current rectifiers.The main current path, adopting a large-capacity current design, uses a low-impedance copper plate to maximize power delivery to the amplifier circuits.How did AMG STA mono achieve better sonic characteristic, in addition to more power than AMG STA stereo ?The standard method for bridging a stereo amp into mono employs a series of op amps (OPA) in order to invert the input signals to one of the stereo amp, thereby creating an opposite phase, which can then be combined to increase power. Conversely, the AMG STA\u2019s innovative bridging circuit utilises a design we call Single-Ended Direct-Inject Bridge Technology, in which the mono mode, in addition to acquiring more than double the power, sounds livelier and more dynamic.Listening ImpressionWith improvements to every area, the bar has been raised for what is achievable with audio performance in small form factor.The AMG STA has a flavor of its own, so it is hard to compare it with the Evolution One, which derives some of its design from or the similarly priced ST-10. AMG STA sounded smooth and relaxing. Detail, resolution, dynamics, and speed are in the ST-10 ballpark, yet the sound is quite different.Drawing comparison with the Evolution One, they shared a trait of ease in reproducing the details of the recording comes afore. However, AMG STA does things differently. While the Evolution One has that inviting warmth, the AMG STA wants to allure the listener. Hence, instead of glitz and glamor, which pulls you in quickly into the performance, the AMG STA has a demeanor that slowly brings you into the music.Tonal qualities of the AMG STA leans toward being full and rich, so instruments and vocals seem to gain extra body, weight, and harmonic richness. It may not be the most accurate reproduction but does make Jazz and Vocal pieces highly addictive. It may take away the raw edge of Rock and Electronic music and sounds less exciting for some.The sound stage has an attractive characteristic. A linear presentation is like having floodlights shining on all the performers such that everyone can be seen equally well. The AMG STA, however, has more of a spotlighting effect, where performers are focused on getting your attention.It is tough to put the sound of the AMG STA into measurable attributes as the presentation is quite different from the other series. You\u2019ll need to try it and hear for yourself.RELATED PRODUCTSABOUT US NUPRIME-X NEWSLETTER PRIVACY POLICYCopyright 2021 \u00a9 Nuprime Audio, Inc. --- brand managed by Nuoem Pte. Ltd.","og_url":"https:\/\/intek-hifi.com\/en\/nuprime-amg-sta-power-amplifier-and-amg-pra-preamplifier-tas-review\/","og_site_name":"INTEK HI-FI","article_published_time":"2021-09-21T06:00:09+00:00","article_modified_time":"2021-09-25T19:28:02+00:00","og_image":[{"width":1280,"height":720,"url":"https:\/\/intek-hifi.com\/wp-content\/uploads\/2021\/09\/nuprime-audio-amg-1280x720-1.jpg","type":"image\/jpeg"}],"twitter_card":"summary_large_image","twitter_misc":{"Written by":"darko","Est. reading time":"2 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"WebSite","@id":"https:\/\/intek-hifi.com\/#website","url":"https:\/\/intek-hifi.com\/","name":"INTEK HI-FI","description":"","potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/intek-hifi.com\/?s={search_term_string}"},"query-input":"required name=search_term_string"}],"inLanguage":"en-US"},{"@type":"ImageObject","@id":"https:\/\/intek-hifi.com\/nuprime-amg-sta-power-amplifier-and-amg-pra-preamplifier-tas-review\/#primaryimage","inLanguage":"en-US","url":"https:\/\/intek-hifi.com\/wp-content\/uploads\/2021\/09\/nuprime-audio-amg-1280x720-1.jpg","contentUrl":"https:\/\/intek-hifi.com\/wp-content\/uploads\/2021\/09\/nuprime-audio-amg-1280x720-1.jpg","width":1280,"height":720},{"@type":"WebPage","@id":"https:\/\/intek-hifi.com\/nuprime-amg-sta-power-amplifier-and-amg-pra-preamplifier-tas-review\/#webpage","url":"https:\/\/intek-hifi.com\/nuprime-amg-sta-power-amplifier-and-amg-pra-preamplifier-tas-review\/","name":"NUPRIME AMG STA Power Amplifier and AMG PRA Preamplifier > TAS review - INTEK HI-FI","isPartOf":{"@id":"https:\/\/intek-hifi.com\/#website"},"primaryImageOfPage":{"@id":"https:\/\/intek-hifi.com\/nuprime-amg-sta-power-amplifier-and-amg-pra-preamplifier-tas-review\/#primaryimage"},"datePublished":"2021-09-21T06:00:09+00:00","dateModified":"2021-09-25T19:28:02+00:00","author":{"@id":"https:\/\/intek-hifi.com\/#\/schema\/person\/02fa1742be92272c2fe50f2579f320e7"},"description":"I don\u2019t have a ton of experience with NuPrime, but here\u2019s a quick, high-level history lesson: The company was founded back in 2014 by Jason Lim, the former CEO of NuForce, and it specializes in boutique Class D amps, media streamers, and many other products. I was very excited to get a nearly complete system of its AMG STA power amplifier and AMG PRA preamp. The amp and preamp combination have the same form factor and were clearly designed to work in tandem. While I\u2019m a fan of mixing and matching equipment from a wide range of manufacturers, there\u2019s something special about listening to the products from a single line, and getting a sense of how they work in tandem.Diving in, the NuPrime AMG STA ($1695) is a sleek, compact Class D power amplifier with a Class A preamp stage and linear power supply. The chassis is simple, with only a metal switch on the front for power, a small white LED indicator, and the NuPrime logo. My review sample came in dark gray, and looked good in my relatively tight equipment rack. As power amps go, the AMG STA never gets overly hot\u2014likely a product of its very efficient Class D output module\u2014though it does get somewhat warm. The back is relatively cramped, and it took a little contortion to get everything hooked up, but that didn\u2019t matter much once it was plugged it and powered on. The power amp supplies a solid 130Wpc into 8 ohms in stereo mode and 300Wpc into 8 ohms in mono mode. That\u2019s one of my favorite features of the PRA\u2014its ability to work as either a single stereo amplifier or in tandem with a second STA as part of a monoblock setup.The AMG PRA ($1795) looks almost exactly like the AMG STA power amp\u2014sorry for the vaguely confusing names\u2014but with two knobs and an LED indicator for channel and volume setting on the front panel. The left knob controls the unit\u2019s loudness compensation feature, which is something I\u2019ll talk about in a second. The right knob plays a bigger role\u2014push and hold for standby mode, push briefly to select inputs, and turn to adjust volume. Two toggles on the front switch between high and low gain and between normal and inverted phase. On the back, the PRA includes one set of balanced inputs and three unbalanced RCAs, along with a balanced and unbalanced out. The remote is heavy enough to break a toe if dropped and seems to be milled from solid aluminum; it performed all the functions I could possibly want\u2014from power to volume control to input switching. Overall, the PRA\u2019s design is simple, but attractive and effective.Before I dive into listening, it\u2019s time to look at the \u201cActive Low Frequency and Harmonic Gain\u201d control feature. To put it very simply, this knob is somewhat like Ye Olde Loudness switch of yore. When turned on it very noticeably boosts bass, without increasing the overall volume. It is an interesting EQ effect, and definitely achieves NuPrime\u2019s stated goal of giving smaller speakers a bit more natural low end. It worked well with my Wharfedale 225s, and actually sounded fairly nice with my Omen Dirty Weekend on its lowest setting. However, through the Polk L600 (review forthcoming), the knob made the bass a little too flabby, which makes sense. (The L600 have a very deep low end, and compensating made the bass a little too intense.) Each setting on the knob is a different EQ curve, and it may be worth experimenting with them to find the one that works best in your setup. For the following review, I kept the knob turned to the left, which turns the feature off. First up, I plugged in a single AMG STA amplifier with the AMG PRA preamp. (I was sent two STAs by NuPrime, so I did half my listening with one, and half with the dual-mono setup.) The single STA was more than enough to power my Zu Omen Dirty Weekends, and made my copy of the recent Ray Charles vinyl reissue Genius + Soul = Jazz sing and scream and shout. Lows were suitably solid, and the midrange really shone with an extremely pleasant smoothness. I never felt as though the AMG STA lagged behind or ran out of headroom powering the Zu DWs, even on this very dynamic recording. Ray Charles sounded fantastic, and his organ really grooved in tight and exciting lines. After trying the Zu DWs, I gave the Polk L600s a shot in the single AMG STA configuration. The Polk speakers are much more difficult to drive than the Zu DWs, but the STA still had plenty of space and headroom to blast through those fiery Ray Charles licks. I decided to try the Analogue Productions vinyl reissue of the RCA release Witches\u2019 Brew to see how it handled something dynamic that might stress its capabilities a bit. Even at its loudest, biggest moments, when the orchestra swells and cymbals crash, I never felt as though the AMG STA was lagging behind, even powering the difficult L600s. The low end was deep and slammed\u2014not quite razor-sharp but not flabby, either. The midrange had an ease to it, a nice, relaxed presentation. Horns were sharp and evenly spaced, and their upper registers had a bit of sparkle. Of the two speaker pairs I tried out, I\u2019d say the single AMG STA worked best with the Zu DWs, likely because they\u2019re easier to drive, but also because they share a similar sound profile\u2014relaxed, with a delightful midrange, a decently solid lower end, and a shimmery treble.I switched over to the dual-mono setup next, which gave me a solid 300Wpc into 8 ohms. That\u2019s way more than enough for the Zu Omen DWs, since they\u2019re easy to drive, but I liked the limitless-feeling headroom that the dual-mono combination bought me. I didn\u2019t find it necessarily sounded better, just more centered and solid, with no straining or restraint. Where this dual-mono configuration really worked was with the Polk L600s, the more difficult pair of speakers to drive. The AMG STA retained its signature relaxed and easy sound, but with that much power on tap really opened up the full potential of the Polks. The backgrounds were shockingly black, and it almost felt as if the AMG PRA preamp was nearly transparent, if you\u2019ll forgive a reviewing clich\u00e9. That deep noise floor allowed the music to shine with a crispness and dynamism that I absolutely loved.Sticking with the dual-mono setup and the L600s, I put on the Tone Poets vinyl reissue of My Point of View by Herbie Hancock. The tune \u201cKing Cobra\u201d opens the B-side, and it features Tony Williams at only 17 years old showing off all his incredible potential, with dancing cymbals that really sparkled through the STA\/PRA combo. Williams\u2019 fills sounded exuberant and rhythmically complex, and the system never compromised or slowed down his fascinating drumming. In the midrange, the piano and horns were smooth and silky with a hint of nice, heavy warmth down in their lower regions. Hancock\u2019s solo was quick and slithering, like the song\u2019s namesake, and each note was clearly delineated. Attacks and decays were on point, which added to the whole rhythmic picture building throughout the song. When the horns massed for the theme, each instrument remained wholly itself and focused, creating a wide sense of soundstage. The STA\/PRA dual-mono combo worked very well with the L600s, since the speakers have a very solid and deep lower end, and the amp\/preamp shines in the lower registers. It was that deep heft that really brought a difficult song like \u201cKing Cobra\u201d to life, and leant the entire ensemble a massive sound. Next up, I listened to Iceage\u2019s most recent album Seek Shelter, streamed via Tidal. On the opening track, \u201cShelter Song,\u201d the fuzzy guitar had a solid growl, while the deep kick drum slammed. The choir added depth and texture without ever straying into chaos. There was a surprisingly strong sense of place and positioning. Despite the sheer number of sounds occurring at the same time, I could still pinpoint each voice and instrument, and I think the monoblocks\u2019 massive amount of headroom went a long way to allowing the weight of the song to shine through. Later on the record, on the hard-rocking banger \u201cSaint Cecilia,\u201d the heavy guitars and screaming solos and choral shouts built into really epic, room-encompassing crescendos. The low end felt solid and intense, while the upper range of the twanging guitar had genuine dazzle. Overall, I felt the PRA\/STA combo played very nicely with some serious rock and roll.I really enjoyed the NuPrime AMG PRA preamplifier and the AMG STA power amplifier. I didn\u2019t waste any time hand-wringing over Class D, and barely even mention it in my review\u2014for good reason. The STA\/PRA combination sounded great, with a heavy low end, a relaxed and pleasant midrange, and just enough sparkle in the upper end to make cymbals shimmer. The interesting loudness function on the PRA and the very nicely made remote control were the kind of simple but useful upgrades over a standard preamp that made this combination feel premium. For many folks, I suspect a single STA will provide enough power, but for those who have more difficult-to-drive speakers, or those who want a massive amount of power on tap and ready to go, the monoblock setup is fantastic. This is a system worth trying and comes highly recommended.Specs & PricingAMG PRA PreamplifierFrequency response: 10Hz to 200kHz; +-0 to -0.1dBTHD: 0.008 %Input impedance: 1M ohm @10Hz\u2013200kHzS\/N: 95dBLoudness compensation: 2.2dB (125Hz)\/4.5dB (100Hz)\/5.3dB (75Hz)Gain: 3.2(High)\/2.1(Low)Inputs: 3x RCA, 1x balancedDimensions: 9.25\u2033 x 11.8\u2033 x 2.1\u2033Weight: 5.5 lbs.Price: $1795AMG STA Power AmplifierStereo power: 2x 130W at 8 ohms & 2x 200W at 4 ohmsMono power: 300W at 8 ohms & 320W at 4 ohmsPeak current: 10A\/15AGain: 26 (stereo) & 52 (mono)SNR: 100dB at 10WTHD+N: 0.006Frequency response: 10Hz\u201350kHz \u00b10.2dB at 8 ohmsInput impedance: 1M ohmSensitivity: 1.2Vrms stereo; 0.95Vrms monoDimensions: 9.25\u2033 x 11.3\u2033 x 2.1\u2033Weight: 8.8 lbs.Price: $1695 Skip to contentNuPrime AudioPRODUCTSProduct CategoriesProduct ListingShowroomsFrequently Asked QuestionsDiscontinuedHOW TO BUYRecommended SystemsA Beginner\u2019s Guide to Good AudioWhat Is High End Audio ?What Is High End DAC ?Amp Comparison & Sonic CharacteristicAmp Design & NuPrime\u2019s AdvantagesMQA & DACsWireless Audio Technology GuideCOMMUNITY & NEWSFacebook & InstagramCustomer BlogCommunity ForumTrade Shows & NewsWHERE TO BUYCONTACT & SUPPORTContact & SupportHelp DeskWarranty RegistrationFrequently Asked QuestionsSearch for:Search\u2026Home \/ Amplifier & PreampAMG PRAEUR 1,795.00The AMG PRA went beyond being a transparent preamp with 1M Ohm input impedance and the best analog source inputs. A user-selectable 4 stage \u201cActive Low Frequency and Harmonic Gain\u201d control gave it distinctive characteristics to enhance the speaker performance, a world-first in preamp design.Category: Amplifier & PreampTag: High-End Series DESCRIPTIONSPECSLOUDNESSREVIEWDOWNLOADThe AMG series front panel embodies its spirit. It is milled from a 15mm harden aerospace aluminum alloy using a four-axis CNC machine with a diamond cutter through a 48 steps process. Design elements such as the 3D \u201cfloating\u201d logo, the curved surface around the front panel switch, and diamond-cut edge bring the quality of ultra-high-end audio products to the affordable range of the AMG series.The design goal for AMG PRA was to deliver a transparent sounding analog preamp with its distinctive characteristics. Several new design concepts were developed and used in the AMG-PRE besides 1M\u03a9 input impedance to achieve the best analog inputs.Users of smallish speakers would often detect a distinct drop in bass response with some audio tracks. Instead of a simple \u201cBass Boost\u201d function that lifts a targeted low-frequency band, a user-selectable 4 stage \u201cActive Low Frequency and Harmonic Gain\u201d control compensates for the lack of bass presence. It achieves some bass extension and a more natural roll-off.Additional features such as the 2 stage gain control and invertible phase control increase the compatibility of the AMG-PRA with other power amplifiers.Technical DetailsThe layout of the AMG-PRA takes excellent care in isolating the sensitive audio signals from the power circuitry. The power circuitry comprising of a star topology power and ground layers is built on one board while a separate board houses the pre-amplification circuit. An isolation layer separates these two boards, which further minimizes interference. The effect is a highly transparent sound that is natural and not over etched.MUSES72320 Digital Volume ControlONE MEGA ultra-wide bandwidth low noise JFET, single-ended Class A input design and MUSES8920 Op-amp produce harmonics similar to vacuum tube amps, which has a \u201cwarm, airy and velvety\u201d sound characteristic.Non-feedback low-frequency domain Frequency Harmonic Modulation circuit provides minimum phase distortion and tone error.Inputs and outputs are fully balanced design.Front Panel SettingsLeft Toggle Switch: Output GainUpwards : High GainDownwards : Low GainRight Toggle Switch: Output PhaseUpwards : Phase InvertDownwards : Phase NormalLeft knob: Loudness CompensationTurn the knob to switch between Loudness CompensationRight Knob: Power and Input Selector and VolumesBriefly press for 3 sec to On\/Off standby modeBrief press to Input SelectorTurn the knob to adjust volumeAMG Remote ControlRELATED PRODUCTSAMPLIFIER & PREAMPAMG STAEUR 1,695.00The AMG STA comprises of several state-of-the-art innovations in power amp design. Its class-leading features include 1M Ohm input impedance, high instantaneous current for power delivery, 700kHz switching frequency, and Single-Ended Non-Negative Class A module coupled with Double Feedback Class D module for 300W mono amp power.ABOUT US NUPRIME-X NEWSLETTER PRIVACY POLICYCopyright 2021 \u00a9 Nuprime Audio, Inc. --- brand managed by Nuoem Pte. Ltd. Skip to contentBEYOND ORDINARYAbout UsNuPrime-XNewsletterPrivacy PolicyNuPrime AudioPRODUCTSProduct CategoriesProduct ListingShowroomsFrequently Asked QuestionsDiscontinuedHOW TO BUYRecommended SystemsA Beginner\u2019s Guide to Good AudioWhat Is High End Audio ?What Is High End DAC ?Amp Comparison & Sonic CharacteristicAmp Design & NuPrime\u2019s AdvantagesMQA & DACsWireless Audio Technology GuideCOMMUNITY & NEWSFacebook & InstagramCustomer BlogCommunity ForumTrade Shows & NewsWHERE TO BUYCONTACT & SUPPORTContact & SupportHelp DeskWarranty RegistrationFrequently Asked QuestionsSearch for:Search\u2026Home \/ Amplifier & PreampAMG STAEUR 1,695.00The AMG STA comprises of several state-of-the-art innovations in power amp design. Its class-leading features include 1M Ohm input impedance, high instantaneous current for power delivery, 700kHz switching frequency, and Single-Ended Non-Negative Class A module coupled with Double Feedback Class D module for 300W mono amp power.Category: Amplifier & PreampTag: AMG Series DESCRIPTIONSPECSFAQ & FORUMREVIEWDOWNLOADThe AMG series front panel embodies its spirit. It is milled from a 15mm harden aerospace aluminum alloy using a four-axis CNC machine with a diamond cutter through a 48 steps process. Design elements such as the 3D \u201cfloating\u201d logo, the curved surface around the front panel switch, and diamond-cut edge bring the quality of ultra-high-end audio products to the affordable range of the AMG series.TechnologyAMG STA PCB integrates ground wire shielding to isolate external interference. The 300 Mhz bandwidth JFET provides ultra-high input impedance and wide-band fast response. The dynamics of the design and the single-ended Class A circuit enriches the natural second harmonic.This design allows the most delicate details in the audio signal to carry through the chain. The level of transparency in sound reproduction is genuinely astonishing in this class of equipment, with a deft in creating a highly detailed sonic imagery.The AMG-STA uses the \u201cSingle-Ended, Non-Negative Feedback\u201d Class-A module partners with a new \u201cDouble feedback\u201d Class D circuitry. The Class D oscillating frequency has increased to 700kHz, which is 1.4 times that of the STA-9.Power CircuitThe power supply uses a 380W special winding power transformer, which has 30% more peak power output of a similar volume transformer.The AC power input from the Inlet Connector to the power transformer utilizes a high current welding line to provide maximum power transmission.Besides, high-frequency 3rd-order AC power filter reduces external noise.A 20A lock wire terminal block connects the transformer to the motherboard, in parallel with two10A peak current rectifiers.The main current path, adopting a large-capacity current design, uses a low-impedance copper plate to maximize power delivery to the amplifier circuits.How did AMG STA mono achieve better sonic characteristic, in addition to more power than AMG STA stereo ?The standard method for bridging a stereo amp into mono employs a series of op amps (OPA) in order to invert the input signals to one of the stereo amp, thereby creating an opposite phase, which can then be combined to increase power. Conversely, the AMG STA\u2019s innovative bridging circuit utilises a design we call Single-Ended Direct-Inject Bridge Technology, in which the mono mode, in addition to acquiring more than double the power, sounds livelier and more dynamic.Listening ImpressionWith improvements to every area, the bar has been raised for what is achievable with audio performance in small form factor.The AMG STA has a flavor of its own, so it is hard to compare it with the Evolution One, which derives some of its design from or the similarly priced ST-10. AMG STA sounded smooth and relaxing. Detail, resolution, dynamics, and speed are in the ST-10 ballpark, yet the sound is quite different.Drawing comparison with the Evolution One, they shared a trait of ease in reproducing the details of the recording comes afore. However, AMG STA does things differently. While the Evolution One has that inviting warmth, the AMG STA wants to allure the listener. Hence, instead of glitz and glamor, which pulls you in quickly into the performance, the AMG STA has a demeanor that slowly brings you into the music.Tonal qualities of the AMG STA leans toward being full and rich, so instruments and vocals seem to gain extra body, weight, and harmonic richness. It may not be the most accurate reproduction but does make Jazz and Vocal pieces highly addictive. It may take away the raw edge of Rock and Electronic music and sounds less exciting for some.The sound stage has an attractive characteristic. A linear presentation is like having floodlights shining on all the performers such that everyone can be seen equally well. The AMG STA, however, has more of a spotlighting effect, where performers are focused on getting your attention.It is tough to put the sound of the AMG STA into measurable attributes as the presentation is quite different from the other series. You\u2019ll need to try it and hear for yourself.RELATED PRODUCTSABOUT US NUPRIME-X NEWSLETTER PRIVACY POLICYCopyright 2021 \u00a9 Nuprime Audio, Inc. --- brand managed by Nuoem Pte. 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