20 Most Recent NAD C372 Amplifier Questions & Answers

Your amp is probably in Protect Mode, meaning you have DC Offset( a damaged amplifier). That will have to be repaired, before you can switch the unit on. If you need more assistance, or would like to inquire about repairing it, please visit my website at audioserviceclinic.com. You may contact me there. Thank you.

Does the TV have a line audio outpot (red and white jack)? If so feed the amplifier input from there.

It could be anything from a blown fuse from a power surge to a shorted capacitor ijn the power supply. There are fuses in all amplifiers. Locate it and test it with an ohmmeter.

Hi Cris

Are there any lights on to the front panel of the amp? Do you here a relay click inside the amp after turnon? The click is the speaker protection relay connecting yuor speakers through to the amp. If it you do not hear this click chortly after you first turn it on, then the amp is in protection mode and will need some repair work done.

I am more than happy to answer any other questions you may have about it, just give me a hoy :) If you are still unsure, or have problems, then before you give a rating for this advice, please get back to me and we can try some more things.
Thanks for using FixYa, If you consider the advice I have given you as sound, a FixYa rating is a great reward for my efforts to help you. Cheers.

regards
robotek

Hi,
If the distortion is also the same in the earphone jack of the unit, this is an indication that the fault was came from the unit itself. This kind of symptoms is technical and needs an experienced to isolate the fault from input circuitry, pre-amplifier stage, and in the sound output section of the unit.
The fault is caused by "Bad input cable cords", "faulty filter electrolytic capacitor" and/or bad solder joints in the said sections.
Replace/swap first the cables to ensure that the fault was not came from bad connections.
If the symptoms still persist after you've replaced the input cables, you must check bad solder joints (cracked, dried, cold solder) in the board. You should work in the brightest area or use table/portable lamp and magnifying glass because these are hard to spot. Check it also in the power supply board.
Let me know if the symptoms still persist after the above solution had been done to assist you further.
Regards,
Jdvillanueva

You DO realize the preamp is duplicating stuff in the Nad C372, right? This Preamps adds nothing but PHONO connectivity and control. That's why they're called "preamps".

Register and download the manual for free at retrevo.com http://www.retrevo.com/support/NAD-C372-Amps-manual/id/8043dj592/t/2/ http://www.retrevo.com/support/Mirage-OMNI-S10-Subwoofers-manual/id/14438ag918/t/2/ Model 2100 Picture and article: Use the Sub Out pair on the Preamp (joined by an RCA Y-cable) for the Sub Input on the sub (duh): http://www.hometheaterhifi.com/preamplifiers/362-a-secrets-preamplifier-and-power-amplifier-review.html?showall=1 Run RCA from the Preamp Main Out to the C372 Aux In to hear any sources attached to the preamp. Or, if you don't NEED the preamp because you don't have a turntable,ditch the preamp and connect the sub using the speaker outputs on the NADS, according to the manual.

HI
Your volume control is broken internally
It will need service. Contact NAD

My first thoughts are to replace the large electrolytic capacitor(s) their will be at least two I think, as they could be getting leaky. Though they could be fully charged up on switch on (hence no noise) they could lose it as time passes and let the 50/60 Hz mains hum in (which they stop). Another cause could be a semi-conductor that has become heat sensitive. This again could be in the power supply or something that has both channels running in and out of it. This is because the noise is in both channels, so can't be something that deals with only one channel, even if there are two of them!
Replace the caps first, if that doesn't solve your problem, then get some Servisol Freezer spray and spray any suspect part (one at a time) when it acts up! If the noise goes you have the culprit.

Other than sympathy, what can we do? Get a pro to look at it.

You'll need to take it in and have an electronics technician fix it. Sounds like it has popped a channel. Sometimes it just happens.
But you might also check your speaker wiring. Sometimes it gets frayed and shorts, which will strain the outputs and sometimes cause damage that doesn't immediately kill the output transistors.
This is not customer serviceable.
Steve Greenfield
Electronic Engineering Technician student
Electronic Technician 20+ years
CET Computers and Consumer Electronics
IPC-A-610D CIS Specialist

Hiya, did you try to swop the inputs as well and see if the problem swops. Try that as the input could also be low. If so try change the cable.

If not there try cleaning out the balance pot with switch cleaner (have to open to that and only you are comfortable).

If thats not there then likely an internal problem and will have to send it in.
Best of luck

Doesnt sound like the selector as it "sometimes" works. Redo the speaker connections on the back of the amp and speakers first. If it persists, swop the speakers and cables, if the problem swops, then it could be inside the speaker or the cable, if still the same then amp has dry joints/loose connections probably

Reverse your RCA input around and see if the problem follows, this will determine if the problem is in the turntable output signal or the preampsection of your amp. If it stays on the same channel, slightly move the RCA that's dropping out signal around. If the signal cuts in and out, you know it's just a weak solder joint on the input rca of the amp. If it does not change, your problem is deeper. Chances are it's a "cold solder joint" on the input section of the amp and would only be a labor type repair and no parts involved. That can be a double edged sword as well depending on how long it takes to find it. If you have to have it serviced, find a local shop that's been around a while, they are likely to be a little more insightful as to the exact problem quicker. Hope this helps

Hi....
ONe of the leads on the CD cable has a broken ground (thats why it hums loud)
The speaker that has only the tweeter working: The woofer is blown in the speakers.
Check also for good solid wire connections at both ends of your speaker cables