The Best Amplifier We've Ever Measured? - NAD M23

[gene]

Ever so often a product enters our lab that absolutely blows us away and redefines a category. The NAD M23 is such a product as you can see in my test report. This type of Class D design marks the end of an era of inefficient linear amplifiers.

The NAD M23 is a 200wpc stereo amp that utilizes the SOTA Class D Purifi 1ET400A reference design to push the envelope of performance and efficiency. Weighing just a tad over 21lbs, this amp can double down with halving load impedance and be bridged to get 1kwatt of power as a monoblock. What is most impressive about this amp is the extremely low noise and distortion performance that forced us to redesign our test fixture to more accurately measure. Is this the best measuring amp in Audioholics 23+ year history of reviewing AV gear?

• Input impedance (R and C) Single-ended: 56 kohms + 200 pF Balanced: 56 kohms +200 pF
• Frequency response (1W into 8 Ohms) ±0.06dB (20-20kHz)
• Rated output power into 8 Ohms and 4 ohms(Stereo mode) 80 W (ref. 20 Hz-20 kHz at rated THD, both channels driven) >200W into 8 Ohm, >380W into 4 Ohm
• Rated output power into 8 Ohms (Bridge mode, ref. 20 Hz-20 kHz at rated THD, both channels driven) >700W into 8 Ohm
• THD (20 Hz – 20 kHz) <0.00069% (XLR), <0.0013% (RCA)
• Signal-to-Noise Ratio >101.7 dB (1W into 8 Ohm); >127 dB (200W into 8 Ohm)
• Clipping power (Stereo mode, at 1 kHz 0.1 % THD) >210 W (0.1 % THD 1 kHz 8 ohms)
• Clipping power (Bridge mode, at 1 kHz 0.1 % THD) > 770W
• IHF dynamic power (Stereo mode, at 1 kHz) 8 ohms: 260 W ; 4 ohms: 520 W
• IHF dynamic power (Bridge mode, at 1 kHz) 1017W
• Peak output current >25 A (in 1 ohm, 1 ms)
• Damping factor >800 (ref. 8 ohms, 20 Hz to 6.5 kHz)
• Frequency response ±0.06 dB (stereo), ±0.054 dB (bridged) 20 Hz -20 kHz -3 dB at 60 kHz
• Channel separation High gain RCA: >97dB, Low gain XLR: >115dB (1kHz) ; High gain RCA: >75dB, Low gain XLR: >96dB (10kHz)
• Stereo Mode input sensitivity (for 200 W in 8 ohms) Low gain: 4.5V (low gain), 2.5V (Mid gain), 1.4V (High gain)
• Stereo Mode Gain 19dB (low), 23.9dB (mid), 29.2 (high)
• Bridge Mode Gain 25.1dB (low), 30dB (mid), 35.2 (high)
• Standby Power <0.5W

DIMENSIONS AND WEIGHT

• Gross dimensions (W x H x D) <0.5W
• Net Weight 9.7 kgs / 21.4 lbs
• Shipping Weight 17.5 kgs / 38.5 lbs

Read: NAD M23 Stereo Amplifier Bench Test Report

 

[gene]

 

[Kvn_Walker]

Very impressive. Wayyyy out of my league, but its nice to know that a buyer is getting true state of the art for their money.

In before "Class D sounds lifeless and digital! "

 

[fmw]

Ever so often a product enters our lab that absolutely blows us away and redefines a category. The NAD M23 is such a product as you can see in my test report. This type of Class D design marks the end of an era of inefficient linear amplifiers.

The NAD M23 is a 200wpc stereo amp that utilizes the SOTA Class D Purifi 1ET400A reference design to push the envelope of performance and efficiency. Weighing just a tad over 21lbs, this amp can double down with halving load impedance and be bridged to get 1kwatt of power as a monoblock. What is most impressive about this amp is the extremely low noise and distortion performance that forced us to redesign our test fixture to more accurately measure. Is this the best measuring amp in Audioholics 23+ year history of reviewing AV gear?



View attachment 57839

Read: NAD M23 Stereo Amplifier Bench Test Report

Good to see new product development has provided some actual benefits. I thought Class D was destined to replace existing designs. Apparently it has happened.

 

[crtguy]

I have the M28 7 channel amp. I use four of the channels to bi-amp my B&W 801 D4s. It all sounds great. The amps never run out of steam and they are totally silent - no background noise, no hiss whatsoever!

 

[mns3dhm]

Looks great but you have to wonder if NAD stands for Not Actually Delivered as they cannot seem to consistently route product to their dealer network. If you look carefully at their product lineup at NAD's online distributors like Audio Advisor, Crutchfield, etc., you'll see that a large percentage of their product lineup is out of stock and has no estimated availability date. For example (and there are many of these), their NAD C399 integrated amp, widely reviewed and applauded, has been out of stock for months on end. In the meantime, NAD continues to promote these items on Facebook and other marketing channels as if everything was running smoothly. Frankly, that's a joke and bad corporate behavior. They ought to at least acknowledge their supply chain problems and be forthright about when and if some of this vaporware will actually reappear in the marketplace. If they don't know when they will be able to deliver product to their dealers, NAD ought to have the good sense to stop hyping them via marketing channels as it's both stupid and counterproductive.

 

[Mikado463]

Impressive, price seems in line for performance and handsome to boot !

 

[buckchester]

Great write-up, Gene. This looks like a very nice amp, but I do wonder why someone would buy this over significantly cheaper options out there. For example, wouldn't two Outlaw 2220 monoblocks provide similar performance for much less cost? This Nad probably has a little more power. But it's like 5x the cost.

 

[gene]

Great write-up, Gene. This looks like a very nice amp, but I do wonder why someone would buy this over significantly cheaper options out there. For example, wouldn't two Outlaw 2220 monoblocks provide similar performance for much less cost? This Nad probably has a little more power. But it's like 5x the cost.

No that's the point. The Outlaw amp won't measure nearly as good w respect to noise and distortion. I don't know of any linear amps that would short of the $50k Levinson.

 

[PENG]

No that's the point. The Outlaw amp won't measure nearly as good w respect to noise and distortion. I don't know of any linear amps that would short of the $50k Levinson.

The AHB2 measured as good or better, but only half as powerful.

 

[buckchester]

No that's the point. The Outlaw amp won't measure nearly as good w respect to noise and distortion. I don't know of any linear amps that would short of the $50k Levinson.

Would you mind elaborating a little? Because I read ASR's review of the 2220 and it looks similar to this Nad to me? Even where the Nad measures better, is that even audible?

 

[PENG]

Ever so often a product enters our lab that absolutely blows us away and redefines a category. The NAD M23 is such a product as you can see in my test report. This type of Class D design marks the end of an era of inefficient linear amplifiers.

The NAD M23 is a 200wpc stereo amp that utilizes the SOTA Class D Purifi 1ET400A reference design to push the envelope of performance and efficiency. Weighing just a tad over 21lbs, this amp can double down with halving load impedance and be bridged to get 1kwatt of power as a monoblock. What is most impressive about this amp is the extremely low noise and distortion performance that forced us to redesign our test fixture to more accurately measure. Is this the best measuring amp in Audioholics 23+ year history of reviewing AV gear?



View attachment 57839

Read: NAD M23 Stereo Amplifier Bench Test Report

Hello Gene,

Everyone seemed to do the FFT (as shown below) with 1 kHz signal, if you still have the unit or if not would you do it in your next one, using a higher frequency such as 3,500 Hz.

I know it won't likely differ by much as can be seen in the frequency dependent test, but you never know. At 3,500 Hz, that is mostly in the range of most tweeters so I am curious to know what the FFT would show, in terms of the 2nd through 7 th harmonics contents (24,500 Hz). I do expect them to be slightly higher than those shown in the 1 kHz test.

 

[gene]

The AHB2 measured as good or better, but only half as powerful.

The difference with an amp like the Levinson is it could drive a fork and not complain. PuriFi is working on a 1kwatt module. Once that's out and implemented, I don't think any linear amp will compete with it at any price.

 

[gene]

Hello Gene,

Everyone seemed to do the FFT (as shown below) with 1 kHz signal, if you still have the unit or if not would you do it in your next one, using a higher frequency such as 3,500 Hz.

I know it won't likely differ by much as can be seen in the frequency dependent test, but you never know. At 3,500 Hz, that is mostly in the range of most tweeters so I am curious to know what the FFT would show, in terms of the 2nd through 7 th harmonics contents (24,500 Hz). I do expect them to be slightly higher than those shown in the 1 kHz test.

View attachment 57845

They will be higher for sure, especially since the feedback of this amp is optimized for 20kHz and below. It's not a standard test to do an FFT up at that frequency but I will look next time I do bench tests.

 

[gene]

Would you mind elaborating a little? Because I read ASR's review of the 2220 and it looks similar to this Nad to me? Even where the Nad measures better, is that even audible?

The Outlaw is a great value like all their amplifiers. It's noise and distortion performance aren't in the same ballpark as this NAD amp. I got 102.7dB SNR at 1 watt! The Outlaw amp according to Amir's test got about 79.5dB at 1 watt. That's a 20dB+ difference in noise. The distortion of the Outlaw amp is also much higher as well.

 

[buckchester]

The Outlaw is a great value like all their amplifiers. It's noise and distortion performance aren't in the same ballpark as this NAD amp. I got 102.7dB SNR at 1 watt! The Outlaw amp according to Amir's test got about 79.5dB at 1 watt. That's a 20dB+ difference in noise. The distortion of the Outlaw amp is also much higher as well.

OK, but how audible are those differences?

 

[Steve81]

OK, but how audible are those differences?

Does it matter? If an amp provides state of the art performance, isn’t that a good thing in and of itself?

 

[buckchester]

Does it matter? If an amp provides state of the art performance, isn’t that a good thing in and of itself?

Yes it matters. Why would I pay a premium for an audio product if I cannot hear what that premium provides?

 

[Golfx]

OK, but how audible are those differences?

Most people who are buying better amplifiers will definitely use the math of bench measurements to help narrow their purchase choices. Audibility of distortion is always a question but I like to think of the higher SINAD numbers as buying insurance against making a purchase mistake. And then there is the sense of pride one gets from owning the best measuring and sounding equipment.

 

[Steve81]

Yes it matters. Why would I pay a premium for an audio product if I cannot hear what that premium provides?

You might consider that nobody else really cares about your personal value system. The amp is out there for sale, and stands on its own merit, regardless. If you don’t think the value is there, don’t buy it vs shitting on the review thread.