NAD Power Amplifiers, which to get (calling NAD enthusiasts)

[funkytwig]

Looking for a used power amplifier. I am currently using a Linn LK85 but my speakers are a bit bright so I think a 80s-era NAD is a good bet.
I have seen 2140/2150 for around £150 and 2100 for £255. There is also a C268 for £325 but this is a 2020s Class D amp so probably not as warm but probably better in terms of clarity etc.
Any thoughts, think its 2100/2140 or 2150? looking for a balance of clarity and warmth.
Current setup

• Linn LK85 amp
• Monitor Audio Silver s6
• Moon D100 DAC
• Project Debuet II turntable (upgrading to systemdek IIx 900)
• Cambridge Audio 651p phono stage

UPDATE: just saw a 2200, which is a later 80s-era amp but more expensive used. This may be the one to go for.

 

[painttoad]

nad has a reputation for great amps with cheap components.

i replaced all transistors in my 2140 besides the outputs and all electrolytics and several ceramics and mylar caps to get rid of hum.

i replaced 2 trimmers but honestly i would suggest replacing all.

great sounding amp and has never given me any problems in the 2 years since updating.

it has no speaker protect circuit. it will give a little noise on turn on/off which can be avoided by turning off speakers before power down and on after power up.

there is plenty of real estate to add a protect board which is on my to-do list but i just have not done it.

if you can not do the work yourself and the unit has not been updated then you should plan on sending it to a shop right away and that is added cost.

if that 2140 has not been gone thru, that price is too high.

 

[leesonic]

The 2140 is the power amp only version of the 3140. All NAD did was use the same circuit board, and not populate the preamp stages.

Stereo Review magazine tested the 3140 amp back in March 1981, I have this magazine and can quote directly from it. They reported clipping power with a continuous signal of 73W into 8 ohms, 94W into 4 ohms, and 112.5W into 2 ohms. Using a 20-millisecond burst test, they got peaks of 103W, 152W and 201W into 8, 4, and 2 ohm loads, stating that the IHF clipping headroom was 4.11dB, the highest they had ever tested. In bridged mode, they got 176W into 8 ohms and 200W into 4 ohms. They also hooked up all their test speakers to make approximately 2.3 ohm load. Driven with the amps 50W LED lit most of the time (remember, they tested the integrated 3140), they said "there was rarely any audible evidence of clipping or other distortions. Comparison with other amplifiers having higher power ratings (60-100W) confirmed that the NAD 3140 could played louder than any of them, and always sounded cleaner".

There are some hot running components in the power supply that bake everything around them. What I do is mount bigger resistors far off the board with long legs, and also replace the regulator transistors with new ones with longer legs, and add additional heatsinking.

 

[OldJBL]

I have two Monitor Series receivers that are the 7100 and 7400 along with a 3240 integrated amp (all have Power Envelope amps). The Monitor Series ones sounds great and have a lot of power. The 7400 has basically the same amp section as the 2400. I am not sure about the 7100 sharing its amp section. I would suggest getting a Power Envelope (PE) series amp as they have a lot of dynamic headroom. This said, going with older NAD components will likely mean you will have to deal with repairs unless you buy something that is has already been run through. This year I delved into the newer class D amps and now use a pair of Fosi ZA3s in a dual mono mode and rarely use any of my vintage components these days. This wasn't a hard decision for me to make. The ZA3 allows the op-amps to be replaced which gives a lot of control over tweaking their output to your liking.

 

[leesonic]

This said, going with older NAD components will likely mean you will have to deal with repairs unless you buy something that is has already been run through.

That actually applies to most older components, NAD or otherwise. I have had Pioneer, Sony, Kenwood, Technics, Sansui amps all with problems. And by the same token, I've had ones (NAD included) that still play well after some 40 years. It's a sad fact that people don't seem prepared to pay what seems like a decent fee for such complicated work as restoring an amplifier.

 

[OldJBL]

That actually applies to most older components, NAD or otherwise. I have had Pioneer, Sony, Kenwood, Technics, Sansui amps all with problems. And by the same token, I've had ones (NAD included) that still play well after some 40 years. It's a sad fact that people don't seem prepared to pay what seems like a decent fee for such complicated work as restoring an amplifier.

I bought the 7400 with a dead left channel for $60 and wanted to save it from the scrap heap. The pre-amp section in the 7400 is outstandingly good and is the same as the 1700. When I viewed the insides it looked like a plate of spaghetti with all the wires connecting the amp, pre-amp and tuner boards. Fortunately, all the problems were with the amp section. There were broken solder runs, the transistors needed replaced and other components replaced that I can't remember from what the tech told me. The 7100 is pristine and came in the original box with a pristine remote control. It had a dead B channel and was able to buy it for $150. It only needed a few solder runs reflowed. The 3240 is pristine and needed nothing done to it and sounds good. I am sure they all need to be thoroughly run through to be brought up to their original condition. I don't plan to do this because I don't see them being used much going forward since I like the sound from the ZA3s a lot. One thing I plan to do with the 7400 is to see what I get having the pre-amp section (fed by a DAC) connected to the ZA3s. This might give me the best of both components.

 

[mbz]

Have you considered the 2200, 2400, 2600, 2700 series. I've picked up a 2700 that had a PE meltdown, currently under repair.
Hopeful it will deliver the goods, currently have a Yamaha M-70 which is not doing it for me.

 

[funkytwig]

Thanks, everybody, lots of great info.

I have two Monitor Series receivers that are the 7100 and 7400 along with a 3240 integrated amp (all have Power Envelope amps). The Monitor Series ones sounds great and have a lot of power. The 7400 has basically the same amp section as the 2400. I am not sure about the 7100 sharing its amp section. I would suggest getting a Power Envelope (PE) series amp as they have a lot of dynamic headroom. This said, going with older NAD components will likely mean you will have to deal with repairs unless you buy something that is has already been run through. This year I delved into the newer class D amps and now use a pair of Fosi ZA3s in a dual mono mode and rarely use any of my vintage components these days. This wasn't a hard decision for me to make. The ZA3 allows the op-amps to be replaced which gives a lot of control over tweaking their output to your liking.

Thanks for this. So if I use a NAD integrated amp and bypass preamp section it is as good as if it was a power amp? So the PE ones are newer but still warm, so seem like a good option. They seem to be going relatively cheap and are late 80s so probably warm sounding. The NAD C340 also looks like a great bet (£100), again bypassing the preamp. Is it the power amp that gives most of the warmth, or is the pre amp the most important (as I said I gave a Linn Konector pre.

Although looking around the C320BEE may be a better bet, but getting mixed messages on how warm it is.

 

[funkytwig]

Have you considered the 2200, 2400, 2600, 2700 series. I've picked up a 2700 that had a PE meltdown, currently under repair.
Hopeful it will deliver the goods, currently have a Yamaha M-70 which is not doing it for me.

The ones I mentioned were the NAD amps under £300 on ebay, would consider all of these. Advice of which is appreciated. As I said ime looking for something warm to compliment my bright speakers.

 

[OldJBL]

Thanks for this. So if I use a NAD integrated amp and bypass preamp section it is as good as if it was a power amp? So the PE ones are newer but still warm, so seem like a good option. They seem to be going relatively cheap and are late 80s so probably warm sounding. The NAD C340 also looks like a great bet (£100), again bypassing the preamp. Is it the power amp that gives most of the warmth, or is the pre amp the most important (as I said I gave a Linn Konector pre.

Although looking around the C320BEE may be a better bet, but getting mixed messages on how warm it is.

The 7100, 7400 and the 3240PE components I have allows you to bypass the amp or bypass the pre-amp by removing the jumpers. Then connecting a source to the main input or connecting the pre-amp to another amp. Here are links to reviews of the 7100 and 7400 with some useful amp information. As for whether the pre-amp and/or the amp provides the sound characteristics, I can't say. If I had to guess it is both. I have not bypassed the amp or used only the amps on any of the NAD components I own. There might be less chance of a breakdown with a newer component but then you might not get the sound you want.

 

[PabloTincho]

Looking for a used power amplifier. I am currently using a Linn LK85 but my speakers are a bit bright so I think a 80s-era NAD is a good bet.
I have seen 2140/2150 for around £150 and 2100 for £255. There is also a C268 for £325 but this is a 2020s Class D amp so probably not as warm but probably better in terms of clarity etc.
Any thoughts, think its 2100/2140 or 2150? looking for a balance of clarity and warmth.
Current setup

• Linn LK85 amp
• Monitor Audio Silver s6
• Moon D100 DAC
• Project Debuet II turntable (upgrading to systemdek IIx 900)
• Cambridge Audio 651p phono stage

UPDATE: just saw a 2200, which is a later 80s-era amp but more expensive used. This may be the one to go for.

If you are in the UK, go for Rotel gear, the RB-870 is a really nice amp with the matching preamp.