NAD 2200 Vintage Amplifier Review

[EJ3]

Did you ever find the answer? My NAD 2200 also has R - & L - grounded.

I am the owner of 6 of these amps (all resto-modded by Peter Williams @ QuirkAudio). I think that I have found the piece of information that may solve what you are wondering about:
Inverted channels for powerful bass:
The greatest power demands commonly occur at low frequencies. Bass signals are in phase (and virtually
monophonic) in most recordings; thus when the bass waveform is strongly positive in the left channel, it
usually is strongly positive in the right channel at the same time. As a result both channels draw current
simultaneously from the positive half of the power supply, while the negative half sits idle. During the
negative half of the waveform, both channels draw from the negative supply while the positive supply
sits idle. In the NAD 2200 the right channel is internally inverted in polarity. When a bass waveform
causes the left channel to draw current from the positive supply, the right channel draws its bass power
from the negative supply, and vice-versa. This efficient usage halves the instantaneous drain on either
supply, allowing much stronger bass to be reproduced without draining the supply.

 

[pjug]

Did you ever find the answer? My NAD 2200 also has R - & L - grounded.

No, I am still wondering about it.

 

[EJ3]

I typically run 2 of mine bridged MONO at 4 OHMs. The third on runs stereo in 2 OHMs (for my sub woofers). My home is a 2400 square foot split level (with 3 levels). The first level contains a large den, a bathroom, an office and an entry foyer. 3 steps up is the breakfast room/kitchen, the formal dining room & formal living room (the location of the stereo). Up a flight of steps with a landing, is the 3rd floor with a sewing room, a formal hallway, a master bedroom, 2 dressing rooms (one with a toilet & one with a bidet), a tub room which also has steam, 2 other bedrooms, each with a dressing room & toilet and a tub room in between the 2 dressing rooms. When I am operating my stereo, I can go anywhere in the house and anywhere within 10-15 feet of the house and clearly here the stereo. I have never had the clipping light come on during this use. I have never had a failure of any type during this use.
Take that with a grain of salt: BUT that is the Empirical Evidence that, at least for me, they haven't failed from this.
I do, however, run only off of a PAIR of 1350 watt Uninterruptable Power Supplies.

I have been tracking my wall outlet voltage which seems to be fluctuating between the higher side of 117V at the lowest & the higher side of 119V (where it is usually) at the highest, never quite reaching 120V.

 

[EJ3]

Did you ever find the answer? My NAD 2200 also has R - & L - grounded.

It's factory. Both restorer-John & I have given out the information as to why.

 

[pantera_rapida]

I have an original pair of NAD 2200's that work great. In mono block configuration they sound better then any of my vintage mid-70's Receivers (even recapped ones) with 165 watts/side. With different pre-amps I've gained more detail, but the wide and deep mid-low end, not to mention the grit of the 2200's is amazing.

I was thinking of refreshing them (caps, etc), but then see that the VTV Purifi Eigentakt EVAL-1 stereo amp is also getting a lot of positive press and whether I should just get one of those amps instead?

Another I was curious about is the Neurochrome Modulus-686.

How would the 2200's compare to either of these? How does the VTV compare to the 686?

 

[DWPress]

Ahhh, you guys are making me nostalgic. I had three 2200's (which I sold to EJ3) and ran them for years bridged for woofer amplification on my active XO 3-way speakers + subs. Before then I used them with various preamps as well in many 2ch systems. They always had enough power for anything I threw at them.

Since my 15" 8R woofers are only reproducing between 50-350Hz I'm now using an Icepower 1200AS2 which has all the power I need and minimal distortion in that frequency range, they run cool and efficiently and in minimal space. The 2200's worked great too, just no longer needed them having gone in a more ClassD direction. I confess, I haven't listened to good speakers (with normal XOs) with any of my Ncore or other ClassD amps so I can't personally comment for full range listening.

A Purifi 2ch amp would definitely be a numbers upgrade over the NAD but, depending on your speakers and typical SPL, you'll probably not notice a difference. The Neurochrome measures really well too operating ClassAB and will require a bigger enclosure with heatsinks probably ending up the size of the NAD. In face if you don't recap your NAD you could gut it and use the case for the Neurochrome. lol

 

[Angsty]

I have a NAD C272. I would not replace it with a Class D amp unless I needed a lot more continuous power. On peak power, the NAD Class G amps cannot be beat on a dollar for dollar basis and longevity.

 

[pantera_rapida]

Just an update since the last post. First is that I acquired a Primaluna Dialog Premium tube pre-amp. I was not prepared for the changes to the sound once I plugged it into my stereo. Up until then I'd used my 1976 Kenwood KR-9600 Receiver (fully recapped) which I thought sounded quite good.

This was a whole different beast: soundstage was bigger, all instruments and vocals took on a more natural sound, but what was even more surprising was detail improved. Cymbal work on a Jazz CD I have was so much more prominent it's like it had been dirty before.

The next addition was a set of Dunlavy Cantata speakers. Up to then I'd been using a pair of 1978 Genesis Physics Model III speakers that sounded quite amazing; detailed, great 3D image, and nice deep bass. The difference with the Cantata is an even better image, more detail and very deep, tight bass.

These new additions are run with the pair of NAD 2200 amps in mono. Both these amps are original, not modified or updated.

After these 2 purchases I had a chance to evaluate 3 different stereo power amps: Musical Fidelity A3CR amp, Simaudio MOON 300A and a VTV Purifi VTV Purifi Eigentakt EVAL-1. The first 2 were no contest; in contrast to the 2200s they were thin sounding, in fact the same music that sounded so good with the 2200s just sounded uninteresting now. I played the 300A for a full day, I couldn't enjoy any of the music I know well, everything sounded clinical.

The big surprise was the VTV. I will note that it accepts XLR only, and I had a pair of plug in adapters into the VTV so I could use RCA. This I'm sure affected the overall performance. So working with what I had the VTV also sounded thin, weak, clinical and uninteresting.

With all 3 of the stereo amps I had to crank the volume up higher. Where I can keep it at 9pm with the 2200s, the others I was up near 10pm and it still couldn't match the sound levels.

Each time, switching back to the 2200s, the music is just amazing. No matter what music is playing with any medium everything sounds great. I was a bit concerned when I realized going from my Gen III speakers (8 ohm) to the Cantata (4 ohm) with the 2200 in mono could be an issue. But then I read this:

Bridging The NAD 2200 is so powerful in the normal stereo mode that few listeners will ever need more. For special situations the two channels of the 2200 can be bridged to form a mono amp of truly immense power. Its rated continuous sine-wave output is 400 watts, while its dynamic power output exceeds 1200 watts into 8 ohms and 1600 watts into 4 ohms. Two 2200s in bridged mode (delivering over 3 kilowatts into a pair of 4-ohm speakers) would cost about the same as an ordinary 400-watt amplifier.

And therein lies another issue (if you can call it that): to get another amplifier that can compete with the 2200s mono level of performance I'm seeing costs many times higher to match them. Add to that their enjoyable musicality with all mediums.

It's easy to see specs on the websites for amps, but until you actually hook them up to your system in your room and hear them, they could sound either fantastic or surprise you with having little synergy. With the setup I have now everything works, and maybe I just got really lucky that the synergy is there.

 

[restorer-john]

Just an update since the last post. First is that I acquired a Primaluna Dialog Premium tube pre-amp. I was not prepared for the changes to the sound once I plugged it into my stereo. Up until then I'd used my 1976 Kenwood KR-9600 Receiver (fully recapped) which I thought sounded quite good.

This was a whole different beast: soundstage was bigger, all instruments and vocals took on a more natural sound, but what was even more surprising was detail improved. Cymbal work on a Jazz CD I have was so much more prominent it's like it had been dirty before.

The next addition was a set of Dunlavy Cantata speakers. Up to then I'd been using a pair of 1978 Genesis Physics Model III speakers that sounded quite amazing; detailed, great 3D image, and nice deep bass. The difference with the Cantata is an even better image, more detail and very deep, tight bass.

These new additions are run with the pair of NAD 2200 amps in mono. Both these amps are original, not modified or updated.

After these 2 purchases I had a chance to evaluate 3 different stereo power amps: Musical Fidelity A3CR amp, Simaudio MOON 300A and a VTV Purifi VTV Purifi Eigentakt EVAL-1. The first 2 were no contest; in contrast to the 2200s they were thin sounding, in fact the same music that sounded so good with the 2200s just sounded uninteresting now. I played the 300A for a full day, I couldn't enjoy any of the music I know well, everything sounded clinical.

The big surprise was the VTV. I will note that it accepts XLR only, and I had a pair of plug in adapters into the VTV so I could use RCA. This I'm sure affected the overall performance. So working with what I had the VTV also sounded thin, weak, clinical and uninteresting.

With all 3 of the stereo amps I had to crank the volume up higher. Where I can keep it at 9pm with the 2200s, the others I was up near 10pm and it still couldn't match the sound levels.

Each time, switching back to the 2200s, the music is just amazing. No matter what music is playing with any medium everything sounds great. I was a bit concerned when I realized going from my Gen III speakers (8 ohm) to the Cantata (4 ohm) with the 2200 in mono could be an issue. But then I read this:

Bridging The NAD 2200 is so powerful in the normal stereo mode that few listeners will ever need more. For special situations the two channels of the 2200 can be bridged to form a mono amp of truly immense power. Its rated continuous sine-wave output is 400 watts, while its dynamic power output exceeds 1200 watts into 8 ohms and 1600 watts into 4 ohms. Two 2200s in bridged mode (delivering over 3 kilowatts into a pair of 4-ohm speakers) would cost about the same as an ordinary 400-watt amplifier.

And therein lies another issue (if you can call it that): to get another amplifier that can compete with the 2200s mono level of performance I'm seeing costs many times higher to match them. Add to that their enjoyable musicality with all mediums.

It's easy to see specs on the websites for amps, but until you actually hook them up to your system in your room and hear them, they could sound either fantastic or surprise you with having little synergy. With the setup I have now everything works, and maybe I just got really lucky that the synergy is there.

The original 2200s are now over 40 years old. In itself, that's not a bad thing, if it weren't for the assembly, soldering and myriad glue issues in those amplifiers.

Do not kid yourself into thinking you have a SOTA giant killing vintage power amplifier. You do not. You have a time bomb, unless it is carefully and respectfully rebuilt. Not some random capacitor jockey in a clown suit and a list of transistors he got from a random guy on the internet.

There's a very good reason most of NAD's 'powertracker' 2200s are long buried in landfill- they were poorly made, poorly constructed and poorly maintained. The good ones can be a work of art and a few members here have excellent examples.

And P.S. Don't believe the hype (or the brochure- I scanned it..)

 

[pantera_rapida]

The original 2200s are now over 40 years old. In itself, that's not a bad thing, if it weren't for the assembly, soldering and myriad glue issues in those amplifiers.

Do not kid yourself into thinking you have a SOTA giant killing vintage power amplifier. You do not. You have a time bomb, unless it is carefully and respectfully rebuilt. Not some random capacitor jockey in a clown suit and a list of transistors he got from a random guy on the internet.

There's a very good reason most of NAD's 'powertracker' 2200s are long buried in landfill- they were poorly made, poorly constructed and poorly maintained. The good ones can be a work of art and a few members here have excellent examples.

Thanks for that info. I'm still looking to see if I can find anything newer to supplant them with, and if I don't I will most likely have them updated. I would like to A/B a Neurochrome 686 but haven't found anyone locally who has one, and I don' t have the skills/tools to build one myself.

 

[EJ3]

And P.S. Don't believe the hype (or the brochure- I scanned it..)

And don't believe the negative hype, either.
Just know that in great hands (for refurbishment [not just a basic re-capping] & a bit of modding, while keeping the design circuitry the same) will result in a very high rating amplifier (when using the lab inputs).

If all is working correctly, it should be just fine.
But, given the age of the components...I would definitely spend the money on a massive refurbishment.
That was (and always was the plan with mine).
I have 3 NAD 2200's that I have had Peter @QuirkAdio do for me and I have 3 that are waiting for me to fund their refurbishment.
Since I was in a bad accident (March 23, 2023) and just had my spinal fusion of C3-C4-C5 yesterday,
It will be a while.

EJ3

 

[Snarfie]

Thanks for that info. I'm still looking to see if I can find anything newer to supplant them with, and if I don't I will most likely have them updated. I would like to A/B a Neurochrome 686 but haven't found anyone locally who has one, and I don' t have the skills/tools to build one myself.

I ones got the 2200 but used as stereo power amp.
Great sound did replaced it with my current NAD C370. I only changed/serviced after 22 years some small capacitors regarding the protection circuite (who was getting slower an slower) an turned a diod for less than 50,- euro. Still running flawlessly. For me besides the NAD the real upgrade was DSP room correction it brings the NAD or other amp to a totaly different level. Depending if you have room modes.

 

[pantera_rapida]

I should mention I use them bridged using the Normal In (not Lab) with Soft Clipping 'On'.

 

[EJ3]

I should mention I use them bridged using the Normal In (not Lab) with Soft Clipping 'On'.

Note the differences in the frequency response plot and the SINAD.
They are both better when you run it using the LAB INPUTS (that is true whether you are running bridged mono or not) :

NAD 2200 Vintage Amplifier Review​

Wow, we have one kilowatt of power coming out of this amp in short duration!

I was surprised that the frequency response was not flat but was relieved to see later in the thread that this is due to insertion of low and high pass filters. So here is the frequency response with Lab input that doesn't have such a filter:

Response now (in green) as it should be, ruler flat to below 10 Hz, and well extending past the 40 kHz limit of this measurement.

I figured the filters may be adding some noise/distortion so re-ran the dashboard again:

Distortion doesn't change but if you look at the noise floor at 20 Hz, it is down by some 10 dB. That improves SINAD a couple of dBs, making the amplifier stand out even more!

Zoomed:

And signal to noise ratio:

Conclusions
Nice to see innovation like this from equipment that is over 30 years old! Shame on manufacturers that produce amplifiers for much less power, more distortion and higher prices these days. No, you don't get a fancy case here and sheet metal is strictly budget category. But you are not going to sit on the amp. The guts are where it matters and NAD 2200 delivers.

NOTE: the output relay on stock 2200 gets corroded and fails over time. There are videos and DIY threads on how to upgrade the relay there to fix the problem. The unit tested here has that fix. Other than that, there are not reports of many other reliability issues even though NAD products are often said to be less reliable than other brands.

Overall, I am happy to recommend the NAD 2200. I almost gave it the highest honors but given the upgraded nature of the test unit, and the fact that used amps may have issues, I avoided that. But you could have easily pushed me to give it the golfing panther.

 

[pavlo_y0l0s]

I got 2200 in the mail now! Super excited! It’s heavy lol. Quality is way better than what they make now! Attention to detail in construction is amazing!

This amplifier has four output transistors + two for the class G additional power. And output stage is triple emitter follower. No wonder it makes so much power!

I took out input circuit board and did not need to solder any wires - every wire has a connector to make it easier to service.

 

[EJ3]

I got 2200 in the mail now! Super excited! It’s heavy lol. Quality is way better than what they make now! Attention to detail in construction is amazing!

This amplifier has four output transistors + two for the class G additional power. And output stage is triple emitter follower. No wonder it makes so much power!

I took out input circuit board and did not need to solder any wires - every wire has a connector to make it easier to service.

Just remember to use the LAB inputs for breaking into the excellent category.
The unit tested here was one of my 6 that I run in various configurations: single, bi amps & tri-amp-ing. In multiple systems.
EJ3
Any questions, I may have an answer (& may not, in which case I'll try to find an answer).
PM me if needed.

 

[pavlo_y0l0s]

Just remember to use the LAB inputs for breaking into the excellent category.
The unit tested here was one of my 6 that I run in various configurations: single, bi amps & tri-amp-ing. In multiple systems.
EJ3
Any questions, I may have an answer (& may not, in which case I'll try to find an answer).
PM me if needed.

Having 6 of those must be nice!
I’ll let you know if have any questions, thank you!
I plan on posting about my experience with the amp here as I progress through rebuilding/updating it.

 

[EJ3]

Having 6 of those must be nicceee!

It's nice that I can use one 2200 for my pair of subs (running stereo at 4 Ohms on a pair of the larger Ported (29 Hz) Radio Shack sub cabs (20-80 Hz) with, installed by me dual 4 Ohm voice coil Pioneer 12" automotive subs running as a 4 Ohm load each. And one 2200 each (at 8 Ohm's for a 6 Ohm load) bridged mono for each of my L & R Dahlquist M-905's (26-20 KHz +-2 Db).
And the other 3 in my alternate systems.
Also a pair of 2100's (half the power, thrice the pain in the but to work on & definitely built to a price point [rectified by Peter Williams at QuirkAudio]).
Which I have in my mother's system at her house.

 

[Machismo]

I happened to notice this thread of the modified 2200, I still have two Nad 2700 THX power amps which I modified back in the day for more power and better sound quality. I am not an advanced electronics guy like some here, but I did some things which worked out just fine.
First of all, because we had loud parties with friends I noticed that the amp always at full volume played couple of beats with really nice authority and then it lowered the volume automatically and then kept that level. And when I opened it, I noticed that there was a one small component limiting the current connected in series to the powerboard. I don't remember was there only one in total or one per channel but you get the idea. So I just took it off/bypassed, since it was heating anyway.
My friend said "I bet the amp will break soon since you did that" but did not happen, I took the limiter components off from both amps and played years after that without any problems. In fact, they never broke. The build quality was good enough. I guess it was just an extra precaution from the factory.

I also added some extra wiring here and there to main voltage circuits to reduce the internal resistance for minimizing the losses, then I doubled the big higher voltage main capacitors by adding another two "floating" on top of circuit board since there was no space anywhere else. I had tested the amp 1 channel loaded with a resistor in a water bucket before the mods, it at first showed the promised 300 watts RMS, but only for a few seconds and then it fell, just like I heard at the parties the volume go down, to 192 watts and it stayed there then.
And after the modifications, the power measured still from the same 1 channel, gave 444 watts and stayed there "forever". So truly continuous RMS over doubled, no more annoying limiters.

So that made the device sound totally different at loud volumes, finally it played like I wanted powerwise. I also changed the output relays to better ones, since originals were too worn out. Worn speaker relays cause the channel to fade out sometimes, there simply is no contact anymore.

At the time, I saw some people change the OP amps of the input board where the rca connectors are, I also tried that with some higher quality ones, but it was only a slight improvement. So I figured, why not get rid of the whole input board and the two front panel potentiometers for level adjustment too. So I completely bypassed those and soldered cables directly from the rca to the main boards, which worked just fine (to my surprise). That did limit the maximum gain somewhat if the source level was very quiet but never too much for my needs, there still was enough gain, which was then of course, not adjustable anymore.

After that final mod the sound was more detailed and easy on the ears somehow.

To the end I just want to add, that while these amps are old, they are still not failing all the time, so they are not hopeless to maintain or anything like that, sometimes you might need to do something yes, but nothing impossible. Good luck!

 

[Doodski]

I happened to notice this thread of the modified 2200, I still have two Nad 2700 THX power amps which I modified back in the day for more power and better sound quality. I am not an advanced electronics guy like some here, but I did some things which worked out just fine.
First of all, because we had loud parties with friends I noticed that the amp always at full volume played couple of beats with really nice authority and then it lowered the volume automatically and then kept that level. And when I opened it, I noticed that there was a one small component limiting the current connected in series to the powerboard. I don't remember was there only one in total or one per channel but you get the idea. So I just took it off/bypassed, since it was heating anyway.
My friend said "I bet the amp will break soon since you did that" but did not happen, I took the limiter components off from both amps and played years after that without any problems. In fact, they never broke. The build quality was good enough. I guess it was just an extra precaution from the factory.

I also added some extra wiring here and there to main voltage circuits to reduce the internal resistance for minimizing the losses, then I doubled the big higher voltage main capacitors by adding another two "floating" on top of circuit board since there was no space anywhere else. I had tested the amp 1 channel loaded with a resistor in a water bucket before the mods, it at first showed the promised 300 watts RMS, but only for a few seconds and then it fell, just like I heard at the parties the volume go down, to 192 watts and it stayed there then.
And after the modifications, the power measured still from the same 1 channel, gave 444 watts and stayed there "forever". So truly continuous RMS over doubled, no more annoying limiters.

So that made the device sound totally different at loud volumes, finally it played like I wanted powerwise. I also changed the output relays to better ones, since originals were too worn out. Worn speaker relays cause the channel to fade out sometimes, there simply is no contact anymore.

At the time, I saw some people change the OP amps of the input board where the rca connectors are, I also tried that with some higher quality ones, but it was only a slight improvement. So I figured, why not get rid of the whole input board and the two front panel potentiometers for level adjustment too. So I completely bypassed those and soldered cables directly from the rca to the main boards, which worked just fine (to my surprise). That did limit the maximum gain somewhat if the source level was very quiet but never too much for my needs, there still was enough gain, which was then of course, not adjustable anymore.

After that final mod the sound was more detailed and easy on the ears somehow.

To the end I just want to add, that while these amps are old, they are still not failing all the time, so they are not hopeless to maintain or anything like that, sometimes you might need to do something yes, but nothing impossible. Good luck!

Does this look familiar as per the 2 PTC inrush current limiter devices that you removed from the +/-95 V DC rails?