(5 customer reviews)

ATI AT522nc Class D Modular Power Amp / 2-8 Channels

Original price was: $ 2,495.00.Current price is: $ 2,395.00.

America’s Most Legendary Brand of Power Amps is ATI (Formerly SAE), On Sale Now at Essence!

Amplifier Technologies, Inc., America’s most prolific manufacturer of high end audio’s best amplifiers has added a new series of advanced Class D amplifiers. The AT522NC amplifier shown here uses Hypex N-Core Class D output modules with ATI-designed input buffers and linear power supplies, available in stereo or mono-block architecture

The AT522NC 2 channel amp is FTC Power Rule rated at 200W RMS per channel at 8 ohms with 300W RMS at 4 ohms and is available with 2 to 8 channels.  ATI’s founder Morris Kessler pioneered the art of manufacturing big high power amps when he founded SAE many years ago.  That tradition lives on today as ATI.

Amplifier Technologies undertook an approach to Class D amplification with the goal of Class AB sonic performance characteristics combined with the efficiency of power and space offered by a Class D design. The results are the AT500NC Series amps. Offered at two power levels of 200 watts per channel from 2 to 8 channels and at 500 watts per channel from 1 to 4 channels, AT500NC amps deliver the classic ATI sound, power and reliability in massively compact 3RU chassis designs. The AT500NC Series amps incorporate Hypex N-Core® Class D output power modules combined with ATI input stages and linear power supplies.

This product series is special order, custom built.*


  • Remote Trigger – Activated from 3.3VDC to 24 VDC via a heavy-duty relay
  • Protection Circuits – Optically – coupled with full automatic reset
  • Toroid Transformers – 40% more efficient than EI type. Each transformer has two bi-filar windings to assure low noise and cross-talk
  • Circuit Boards – Double-sided, FR-4 glass-epoxy, computer-grade boards are assembled in-house
  • Soft Start Circuitry – New micro-processor controlled turn-on board first ascertains input voltage and configures transformers for 120V or 230V operation then ultra soft turn-on timers reduce in-rush current to a minimum. Multiple units can be turned on without tripping circuit breakers eliminating the need for sequencing
  • Amplifier Output – Hypex N-Core NC-500 Class D amplifier modules with ATI’s custom input buffer insures edge-of-the-art operation
  • Power Cord – 20A IEC power inlet with detachable, 3-wire cord
  • 7-Year Warranty – Parts and labor against defects in parts or workmanship

Select A Model

RackMount Kits

Power Cord

Power Voltage



The AT522NC amplifier breaks new ground.  It’s the first ATI amplifier to use micro-processor control for turn-on delay and feature automatic AC voltage recognition and configuration. The amplifier recognizes whether it’s hooked up to 120V or 220V nominal power and automatically self-configures. The amplifier also incorporates a new and novel “sleep” circuit. When the amplifier receives no input signal for a period of 10 minutes, power is removed from the output modules and a front-panel LED begins to flash. As soon as an input signal is detected on any channel, normal playback operation resumes instantaneously.

Per Morris Kessler, ATI’s president and chief engineer, “We are excited to offer amplifiers with ATI’s legendary high performance and reliability in designs that reduce amplifier weight by up to 50%.”. And, with rated distortion below 0.02% and signal-to-noise ratio of -123 dB (minimum, referenced to rated output), each amplifier in the series is capable of playing back the full dynamic range available on today’s lossless recordings.

All NC Series Amplifiers are Class D using N-Core Technology and Linear Power Supplies with Automatic 117 / 230 Voltage selection in a 3 RU chassis.

Because Class D Power Amps are 90% efficient, they can convert 90% of the electricity they consume into watts you can hear, only 10% of the electricity turns into heat  Class AB Power Amps are 50% efficient, they can convert 50% of the electricity they consume into watts you can hear, the other 50% is dispersed as heat into the air by large heat sinks that channel the heat away from the amp. 

Class D design requires a much smaller chassis because it stays cool during operation which translates into a lower production cost and retail price with no sacrifice in performance.  In fact, today’s Class D amps outperform the Class AB designs with lower distortion and noise, lower weight, and much lower cost.  Its modern thinking at its best.  More power, less money, better sound….that’s ATI Class D power amps.


Additional information

Weight 49 lbs
Dimensions 10.5 × 17 × 5.75 in



Number of Channels
2 to 8

EIA 1kHz Output Power at 8 Ohms*
250 Watts

EIA 1kHz Output Power at 4 Ohms*
375 Watts

FTC Full Bandwidth Output Power at 8 Ohms**
200 Watts

FTC Full Bandwidth Output Power at 4 Ohms**
300 Watts

Input Sensitivity for Full Rated Power
1.6 Volts

Frequency Response at Rated Output
20Hz to 20kHz +0, -.5dB

Phase Response
+5 to -15 degrees from 20Hz to 20kHz at 1 watt

Signal-to-Noise Ratio “A-Weighted”
Greater than 123dB below rated FTC Full Bandwidth Output

Total Harmonic Distortion (THD)
Less than 0.02% at full rated FTC power

Intermodulation Distortion (IMD)
Less than 0.03% at full rated FTC power

Load Impedance
Safe with all types of loads. Rated for 4 to 16 ohms

Power Bandwidth FTC
+0, -3 db from 20 Hz to 40 kHz

Damping Factor
Greater than 5000 from 10 Hz to 400 Hz

Greater than 100 dB from 20 Hz to 20 kHz

Voltage Gain through RCA
27.8dB ±0.2 dB

Voltage Gain through XLR
27.8dB ±0.2 dB

Slew Rate
>60 V/µs

Input Impedance
Nominally 47 KOhms

Remote Trigger Voltage
3.3 to 24 Volts DC at 5 mA or greater

DC Output Offset
Less than ±10 mV

Power Requirements
120 VAC / 230 VAC (other voltages available on export models)

Chassis Dimensions (W x H x D) Inches
17 x 5 3/4 x 10 5/8 (2-4 Channels)
17 x 5 3/4 x 15 1/2 (5-8 Channels)

Net Weight (lbs/kg) Model Dependent
39 to 66 / 18 – 30

Shipping Weight (lbs/kg) Model Dependent
49 to 76 / 23 to 35

5 reviews for ATI AT522nc Class D Modular Power Amp / 2-8 Channels

  1. David Vaughn, Sound & Vision, May 2017

    David Vaughn, Sound & Vision, May 2017 – December 15, 2020

    “As you can probably tell, I really liked these ATI amps. They offer everything one would want: powerful dynamics and uncolored sound. Given their Class D architecture, they run extremely cool compared with my main reference Class A/B amp—which isn’t such a benefit in the cold of winter but will be a godsend come summer. And now I’m really looking forward to summer because I liked these amps so much, I actually bought them as an upgrade to replace my Parasound A 51, a well-established audiophile/videophile favorite that has been my reference for many years and through many other amplifier reviews. That’s quite an accomplishment for these ATI amps, but I feel confident in saying they deserve to be placed in the same high-end category—and they represent extraordinary value to boot. I can’t recommend them enough.” David Vaughn, Sound & Vision, May 2017

  2. Amir M, Publisher of Audio Science Review, Nov 2019

    Amir M, Publisher of Audio Science Review, Nov 2019 – December 15, 2020

    “The ATI AT522NC seems like a solidly built amplifier based on Hypex NC500 modules. ATI builds amplifiers for many other companies and this competence shows up in this review. Performance is of course limited by what the NC500 module can do. Use of linear power supply defeats the size and weight advantages of common class D amplifiers. It may provide better peak power rating — something I wanted to test but forgot. 🙂

    Overall, I can recommend the ATI AT522NC stereo amplifier.” Amir M, Publisher of Audio Science Review, Nov 2019

  3. Rich B, Audioholics May 2019

    “The AT522NC woke up the Revel M20’s, adding fun to many familiar recordings. Female vocals lifted, presenting a great emphasis on dynamics and sibilants. The dynamic and hard-mic’ed vocals on Sarah Jorosz “Undercurrent” (HDTracks 96/24) are not forgiving on any system. Driving the Salon2s, the AT522NC drum strikes hit hard, demanding attention, clearly capable of delivering room-shaking bass from the Salon2’s woofers. The AT522NC is no lightweight amplifier but the weight and heat reduction are benefits worth considering. ATI’s NCore amps are popular for Home Theater. Judging from ATI’s styling, they are clearly targeting that market.

    Class-D has been described as dark and often lacking bass when driving difficult loads. This is not the case with the AT522NC.”
    Rich B, Audioholics May 2019

  4. Brent Butterworth, Home Entertainment & Design – December 15, 2020

    “ATI has one refinement on which practically every authority, from the ultra-conservative “everything-sounds-the-same” engineer to the rarified audiophile, agrees: fully differential construction. Author G. Randy Slone, the expert who wrote High Power Audio Amplifier Construction Manual, describes differential construction as the “Cadillac” of amplifier designs; consider this accolade the highest level of compliment and forgive his limited familiarity with luxury automobiles.

    Intimidating as it may sound, fully differential construction is fairly easy to understand. A differential (or mirror-image) amplifier uses two identical amplifier circuits, where only one was used before. One amplifies the positive half of the audio signal; the other amplifies the negative half. This design cancels out noise that ordinary amplifiers would pass on to your speakers. It also operates at twice the speed of an ordinary amp. Of course, doubling up on circuits adds considerably to the cost of manufacturing, so fully differential construction is rare, found mainly in very high-end, audiophile-oriented amps.” Brent Butterworth, Home Entertainment & Design

  5. AVS Forum – December 15, 2020

    Audio Visual Science Forum Dec 2019
    ATI’s “True Balance” Differential Design Architecture
    “Getting back more specifically to amps, I really need amplifiers that can do certain things for me, and the ATIs have all that, plus more. I want to go full balanced instead of single ended, and ATI handles that, plus the “true balance” differential design architecture of the amp really fits the bill for me. I want lots or headroom, and with three 200W channels per amp being fed off two gigantic toroidal transformers, there’s no bottom to this well–or at least I can’t find it.

    About that 200W/channel–it’s not really true. Are they liars? Well, no, my actual measurements find them to be running about 210-220+W/channel, all channels driven from full range 20Hz to 20kHz noise. So it’s not your typical, lame 200W/channel with one channel driven only at 1kHz.

    A nice surprise is the soft start circuitry. I have a single 20 Amp circuit dedicated to this system, and with the amps connected via DC triggers to the pre, a push of the on button brings the whole system up in an orderly fashion, without pops, thumps, thrown breakers, or house wide brown outs. I can take the Niles IPC6 sequencer right out of the system.

    All in all, I got everything I needed in an excellent pair of amps at a great price, made locally in CA, USA. Plus, I didn’t pay extra for what I didn’t need: fancy billet Aluminum front, big prestige brand name, expensive marketing campaign, and huge overhead. Instead, when looking at them up close, I can see the quality construction, the attention to detail, the careful engineering, and the thoughtful, useful feature set.

    These are well worth the $$$$.”

Add a review

This site uses Akismet to reduce spam. Learn how your comment data is processed.