Need info for NAD 3140


i have purchased a NAD3140 for the amazing sum of $14.99cdn, a little cleaning and some new fuses and the thing works like a charm. Try as i might, i can't find any information on this machine. went to the nad web site and they had no info, tried emailing them and they told me it was to old for them to have any information. if any body knows anything that would be a great help


If it's any help, I have a user manual for the NAD 3140. I 'retired' my 3140 about ten years ago, when the controls started getting 'dry'; but I've just brought it back into service to provide enough oomph to fill the 18ft square room that I now use as a music room. Lovely amplifier; not the best, but in terms of value for money, hard to beat at the time I bought it. I saw it criticised as having a "muddy" sound; don't know who said that, but he must have had a faulty unit.

i also have a NAD 3140, looking for any information on it. it think its faulty, and i have no idea how to go about fixing it. i am very experienced in electronics but dont know where to start on a stereo amplifier. any information that can be provided will be greatly appreciated

I also have a NAD 3140, but would like two. Ryan S do you want to flog yours?

hi guys, thanks for the replies,

Brown, would you be able to tell me what is "SLC" button for? I found that this little jem is just sweet. I bypassed the "EQ 45/70hz" button, i also replaced the speaker clips with nickle plated banana plugs. This made a huge difference.

Ryan S, tell me what the problems are and i can then figure out were to start the problem solving

thanks again,

Leigh Sparrow
SLC stands for Speaker Lead Compensator, a circuit designed to do just what it says: compensate for signal degradation over long lengths of speaker cable. If my memory serves me correctly, NAD consider long lenths to be more than 10 meters, and also that the cable was of pretty low quality. I don't use the button myself. I could hear no difference with my average standard cables of 5-8 metres

I just picked up an NAD 3140 on Ebay. It works, needed pots and switches cleaned... but sounds clean with a nice steady soundstage. It has more than enough for the Klipschs and a sweet phono stage. Worth the $24 :) I too would like to bypass the needless nonsense, upgrade the speaker connectors and the caps in the signal path. This thing really needs a better volume pot. So, if one of you has a schematic and is willing to share or sell a xerox of it... or PDF scan... please... I would gladly pay for the trouble and share my upgrading experiences. Thanks.

I just found this string while looking for comments on the NAD 3140 - I own one, have had it for some 16+ years. It needs repairs, the controls were getting dirty and now it has just quit - powers up but getting a rather loud and steady thud out of the speakers - I found a local shop (northern VA.) that charges $69 to check it out - will apply it to the cost to repair. I was just seeking comments on how to proceed. I do have all of the original documentation that came with it and would be happy to share it with anyone who would like it.

I also am a long time owner of a 3140. Very nice entertainment machine when bridged and paired with the 2140 amplifier. Recently I started getting a random scratching in the left channel of the 3140 that is not affected by the volume or tone controls. Any troubleshooting hints?



I have both a 3155 and a 3140, and both share the same weaknesses: Lousy contacts and pots. I had a lot of scratching, distortion and occational no output until I cleaned the input selector (and other switches). I guess, NAD uses the switches fo both power and signal. Anyway cleaning solved it all.
Also, my 3140 lost one output amplifier during a loud practice session with my band, and I am going to replace the heatsink with something bigger, as this is the second major weakness with these amplifiers.
If any of you come across a schematic, I would be very happy to receive a copy.
Please copy me directly on replies.

Hallo! I do also have problems whit the volume control! Do any of you have an ideay how to repeair it??? I also have problems whit the outputs for the speakers! any ideay how to fix it??? P.s. I´m not very good at English because i´m from Denmark and i´m only 15 years!

Hi.I have just become the owner of a 3140 and a 2140 power amp.Unfortunatley they came without any user manuals.Could any body out there please help.Thanks.

Try to source the following service manuals ,

NAD 3020 Amplifier

NAD 1300 Pre Amp

Received both units , for repair , ref my

i hyave a NAD 3155 and one of the channels has gone down....any ideas what steps I can take to repair it?
I can't see any galss fuses that I expected that I might have to replace ...apart from the one on the power switch that looks fine
thanx in anticipation


I can't find any information about amplifier NAD-3130. If any body knows anything that would be a great help, it's can be schematic diagram, link to the site, or any possible information.
Thanks for all

I have a 220v NAD 3140 since 1981. It switches on but no sound from the speakers. Fuses seem ok. In the past, use with a Celestion SL6 speaker (difficult to drive) had hurt the speaker but it used to work. Latest attempt to make it run was after a gap of 15 years.

Grateful for guesses on what could be wrong with the machine. Since local expertise is poor would need these guesses in order to coach the technician. Also to avoid being taken for a ride.

hello, mu name is adam, my grandfather gave me his nad 2140 amplifier, how much is it worth today???
thankyou, hear from you soon

To a collector, maybe $50-$75.

To anyone else who wants a good or usable amp, $10 or less. To a budding electronic noodler maybe $25.

This amp must be over 20 years old.

To most sensible people it isn't worth anything.

G-man, how long does an audio electronic equipments last? I have 25 year old marantz, and it sounds good to me. When you say NAD 3140 isn't worth anything, is it because of the age?
Can you elaborate on that, 'cause I love picking up used gears on the audiogon, or ebay.

Mark Adams
3140's go for about 110$ on ebay. 2140's are about the same.
Back to the topic, would someone please post specs on the 3140 from the manual? Is it the same as the 7140, minus the tuner, on the nad website?

I got some questions. All of the controls are noisy except the bass, volume, infrasonic, and mono. The balance detent is loose but works fine. Also the volume control is uneven, the left channel just drops out at very low volume levels. This happens from about the 3rd dot down. How do I clean it or is it better to replace them?

Is the red power light soposed to turn on with the unit or is it some sort of warning?

Mark Adams
The red power light is supposed to turn on.

Hi Jason Steffes

got this from

Probably is good for you?


The amplifier incorporates protection circuitry
against conditions such as overheating, short circuits,
and DC off-set. Under normal conditions, this indicator will not light up and the unit will operate normally.
If however one of the decribed conditions occur, the indicator will light up red and the unit will stop working. TURN DOWN the volume all the way and SWITCH OFF the amplifier IMMEDIATLY.
Investigate the cause for the protection circuitry to trip, such as a short circuit in any of the speaker leads or any wire touching an adjecant terminal at either the amplifier's or loudspeaker's end.
If overheating was the cause (the amplifier's casing will be very warm) ensure the ventilation slots at the bottom and top are not blocked. Overheating can also occur by playing very loud for a prolonged time. Wait for a couple of minutes for the amplifier to cool down before switching it on again.
If the protection circuitry remains engaged, even
after the amplifier has cooled down sufficiently and all connections have been checked you will have to consult your NAD dealer .

Mark Adams
The 310 is not the same as the 3140. The 310 is much newer. The red led on the 3140 says "Power" next to it. It is power light not a protection indicator. I agree that the choice of color was poor but that does not change its function.

greetings, if anyone would happen to know the nad website address,please send it to me i have a 240 preamp and would like to get an oweners/operators manual for it,thanks

Hi there Alvin.

The address to NAD's website is:

I also found a site where this guy claims to have a whole lot of old service manuals. But the site seems to be quite old.
Apparently written in September 2000, might still be worth checking though.
Good luck y'all

Wow! Hehe!
I found yet another link on the topic.

They seem to have a lot on

Sorry to hijack the thread but does anybody know how to bridge the 3155? Is it the right input and then connect the speakers over the positive terminals? Should I short circuit the negative terminals? (I don't have the manual)

Mark Adams
Bridging is in one of the faqs on the NAD website. From what I have seen, all amps use the same procedure to bridge regardless of brand.

Unregistered guest
How does one go about cleaning the connections? I have a NAD 3300 integrated that is developing a lot of distortion.

I somewhere have some documents of the nad 2140/3140 it is tech. specs + a review of the amps.
only problem is it is in the dutch language.


New member
Username: Cpfletch

Post Number: 3
Registered: Feb-04
I just got my NAD 3140 back from the shop. Had to make a Buy or Fix decision, opted for fix -- Q Audio in Cambridge MA fixed a number of problems for me including one channel dropping out or failing, scratchiness in controls, EQ control not working, even fixed the 2 LEDs on the front that were burned out. Total was $138, $$ well spent IMHO. Would have preferred getting a C370 (reconditioned C370s available at Q for $419) but...

Unregistered guest
I have a a NAD 2140 that just failed. Resisitor R622 overheated to the point that I can't read its value. If anyone can tell me the value (or its colour bands) I'd very much appreciate it.

Dave Soubriakov
Unregistered guest
I have a NAD 3130 amplifier, and for sentimental reasons and perhaps because I'm an idiot I want to keep it and find a set of stereo speakers to suit it. I am pretty well absolutely ignorant in these matters. Can anyone suggest what I should be looking for in the way of speakers? To quote a specification I have found: "The NAD 3130 stereo amplifier, while rated at a modest 30 watts per channel, has a high-current
output stage that delivers short-term bursts of 60 to 80 W/ch, not only at 8 ohms but also with
the complex impedances of real loudspeakers". That might make sense to someone.

Unregistered guest
I am the original owner of an NAD 3140 which I have not used for years. It works well and I have the manual. If you are interested in making an offer to buy it, just email me with NAD in the subject line. I also have the NAD 4150 Tuner to sell as well.

Unregistered guest
The main problem I have had with my NAD 2140 power amp is dry joints on the PC board. If you look carefully, after removing the base cover plate, you will see that some of the component leads barely contact with the board. There is a loose "ring" of solder at the joint, or a fine circle like a crack in the solder.
Take your small soldering iron and go over the whole board.
Be very careful not to "bridge" the solder to adjacent joints.
Instant reliability, except the worn out pots.

Unregistered guest
Vu meter:
i just bought a nad 3140 for some 7$ or so that was in quite bad shape.. or not really (Blown fuses, damaged transistor (nec b536) and a blown capacitor on the vu meter, had most of the parts and now it works like a dream, exept for the vu meter, anyone who could tell me the name for the capacitor? the leds ar blown as well but i just ordered new ones. thanx

Unregistered guest
NAD 3020 amp. At switch on I get a buzzing through both speakers for about 10 seconds then it disappears. Can anyone help with a solution to this.

Unregistered guest
sounds like the amp needs to heat up, i don't know what because it is solid state. but o well. I work for a sound shop in starkville and i just did various upgrades and repairs on a 3140. It's not a bad amp, but it's not the best. We deal mostly with Audio Research and Marantz receivers and amps.. Anyways, if you need any help or suggestions i should be able to help, i just completely went through a 3140

Unregistered guest
maybe you could tell me what the S.L.C button is for and why there are bot Lab in and Normal in on the amp? it also makes (just sometimes) a little noise when i change a track on a cd, anyone who can tell me what that is an how i can fix it? the leds turned out to be just fine, the just wont glow, but everything seems fine (havent tested the IC`s yet) any idea what`s the reason why they wont glow or ar they just not surpose to unless you turn the volum REALLY high? :-)

Unregistered guest
The left channel on my NAD 3225PE has gon away...
R543 is burned out and the orage errh..thing next to R435 seems to be broken too...
Does someone know where I can get some schematics or service manuals free?
Email me at

Unregistered guest
Hi, If any of u guys managed to get the manual/scematics of the 3140 I`d love to get a copy. ( rafbm (a) hotmail. com ).

Tnx :-)



Unregistered guest
hi guys i have a really simple question about the 3140. what exactly happens when you turn the speaker selector to "off"? should the amp be turned on or run in this mode? I've found that my headphones sound great through the 3140 but the speakers continue to run while you listen to the headphones (not very useful when other people are trying to sleep). If i turn the speakers off, does it mean that the amplifiers continue to run with no load, or is the 3140 smart enough to shut off the amps in this mode? any replies would be appreciated, it's my only amp right now and i don't want to ruin it. Thanks a bunch!

Unregistered guest
I have a NAD 3140.
Yesterday a short circuit occured on the right speaker output => no more sound (or very low level) on the two outputs!
If someone can help me to repair it...for example, can you send me an electronic schematic?
Is there fuses on speakers outputs?


Lars Erik S.
Unregistered guest
Hi. I have a NAD 3140. I have had it since 1981, and I have always been very satisfied with it. I can't find my manual, and I need to know how to bridge it. How to connect speaker when bridged, and whitch input on amp in (left or right) to use. Thankful if someone can give me an answer on this.

Unregistered guest
dear all - my NAD 3140 is all of a sudden causing the speakers to make a slight hum when we turn on the amp. If I turn the speaker selector from "A" to "OFF" then the hum goes away. If I activate a music source, the hum remains but of course the music covers up the hum, more or less, except at lower volumes. None of the buttons on the 3140 are depressed and everything is in the basic setting. My signal source is set to tuner, I'm running all signals through a NAD 3140. The hum is present whether the 3140 is turned on, or not. Help! And thanks.

Unregistered guest
dear all - my NAD 3140 is all of a sudden causing the speakers to make a slight hum when we turn on the amp. If I turn the speaker selector from "A" to "OFF" then the hum goes away. If I activate a music source, the hum remains but of course the music covers up the hum, more or less, except at lower volumes. None of the buttons on the 3140 are depressed and everything is in the basic setting. My signal source is set to tuner, I'm running all signals through a NAD 1600. The hum is present whether the 1600 is turned on, or not. Help! And thanks.

Unregistered guest
dear hi fi nuts,
i have just purchased a nad 3140 on ebay and probably paid too much for it, $290.00 australian dollars. can anyone help me locate an owners manual and a circuit diagram. (it sounds fantastic and is in great condition).
cheers glyn.

NAD 3140 for sale (best offer).

Located in Pennsylvania.

Original owner, purchased in 1980. Used for a few years. Been in box for last 15+ years. In excellent condition. No manual.

Email me for details.

Unregistered guest
NAD 3140 for sale (best offer).

Located in Pennsylvania.

Original owner, purchased in 1980. Used for a few years. Been in box for last 15+ years. In excellent condition. No manual.

Email me for details ""


Dear HiFi experts - I would be most grateful for your advice.
We have a NAD 3140 amplifier purchased in 1981. About 3 or 4 years later it developed an intermittent fault - a very loud humming vibrating sound that would "rock the house". We did ask someone about it but the system would never "perform" to enable him to identify the sound.
Over the last few years it has become more frequent and this last year the system can't be left playing without someone nearby to turn everything off when it happens.
We have just been advised that this sound is the result of dry joints. Before we take the system in to be looked at could someone please confirm if this noise is a symptom of this problem. Many thanks.

Unregistered guest
I aquired my 3140 out of the skip of hi-fi shop a little over six years ago for free, even walked into the shop with it under my arm an' asked if they minded and was told by the chuckling owner that it had been deemed as NWR (not worth repair)
Cant say as I blame him, the circuit board contains many ugly hacks implemented by the makers. After touching up the solder joints and repairing the section of track that been vapourised it continues to give a stirling performance.

Silver Member
Username: Sun_king

Leeds, West Yorkshire UK

Post Number: 243
Registered: Mar-04
What's not worth repairing to one person IS worth repairing to another. Just because you can buy cheap amps new for less than the price of fixing an old one it doesn't always mean it shouldn't be done. I haven't heard the 3140 but I do have the 3130 in my bedroom system and it's a great amp. Sounds so much sweeter than the latest budget amps. They do suffer from having cheap switches and pots - they take to cleaning a few times but after that I'd just solder in some new ones. Volume pots and switches are very cheap to source. If you also have problems arising from dry joints etc it is worth cleaning the circuit board and resoldering. I wouldn't swap my 3130 for a current NAD C320BEE - and that's one of today's better budget amps.

Unregistered guest
Hi all,
I have the NAD 3140 since very long time and now I don't have the manual or instruction....
I'm searching these and I would pay them if someone could send to me. I get also as scannering or photocopied...

Unregistered guest
I have a 2140 that I bought in the UK in (about) 1983. A few weeks ago my 1 year old managed to knock over a speaker and short the output on one channel. The 3.15A glass fuses on one channel were blown. That was easily fixed. I changed the power supply electrolytic capacitors, as the amp is 20 years old and I would be pretty sure that those caps are dry of electrolyte. I considered changing all the others but there were too many, so I just put it back into service. The quality of the old phenolic PCB used in the 2140 is really bad and there were plenty of solder joints becoming crystalline, which I re-soldered. I would recommend anyone else to check the joints before closing the cover.

Unregistered guest
I have just bought a 3140 and am also looking for a manual (or scan of one). If anyone can help, please post here or email me.

Meanwhile, could anybody please tell me what the various buttons do(including the SLC button on the rear of the unit).

Finally, what speakers have you used / would you recomend with this amp? I listen to a lot of classical and jazz, and most genres of popular music from the 30s, 40s, and 50s, as well as an eclectic mix of more modern music.

Silver Member
Username: Artk

Albany, Oregon USA

Post Number: 720
Registered: Feb-05
Paradigm Reference series, B&W 700 series, Tannoy, and on and on. Lots of great speakers out there. If you can find an NAD dealer and see what speakers they're playing. Take some of your favorite music and do some auditioning.
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