Question about NAD C320 2-Channel Amplifier
Not so much a problem as a problem + solution :-)
One channel on my C320 had the above problem. I read online about capacitors drying out, so opened up the case & sure enough the top of a cap on the bad channel had it's top opened, so dryout seemed likely. Think it was C216 at 2200uF/6.3V. Can be replaced by removing the underside pane of the amp & desoldering the bad component - no need to remove the main board. Used larger voltage replacement, this isn't usually a problem. Now back in service & sounding fine.
SOURCE: NAD 302 Amp
Try Earex wax softener, worked for me! Seriously though, are you sure it's the amp, could someone have cooked your speakers without you knowing? Have you checked the media source? Garbage in equals garbage out with any system. Your terminology leads me to think you are an audiophile, so have you checked the stylus? Have you put in some new furniture or rearranged the room. This can make a big difference to the way a system sounds. Check all the usual things like your signal connections. If you have a PC to hand in your listening room, use it as a sound analyser, plug a microphone in and connect the line out into your amp you should be able then to measure the responses of your setup with white noise, swept tones and impulses for room dynamics. I seem to remember there are freeware utilities for this kind of thing. Good luck
Posted on Sep 22, 2007
This sounds like the "pre-amp" section is cutting out or there is some interruption in the signal path. A few things to try:
1) With the unit off, try "working" the volume,balance and tone controls. This means, turn them up and down a number of times to clear any debris that may be in the controls themselves.
2) Work the input selector switch the same way if it is a rotary switch.
3) Try turning on/off the tape monitor switch a few times.
4) Keep track of whether this problem is sensitive to heat. Does teh channel shut down more quickly once the unit has been on for a while?
Lastly, if you can solder, look for any solder joint that appears grainy or has rings and resolder it.
Update this with your results and we'll continue on...
Posted on Jan 16, 2009
My solution was actually indeed the output protection relay. What I did was to open up the relay and use contact cleaner and a very fine abrasive to clean the contact surfaces of the relay. After that, the problem was gone!
The way to diagnose this for me was to run the amplifier open until the problem recurred and to simply tap the relay's box. The sound came on immediately, and I was convinced.
Posted on Feb 05, 2009
The AH may denote "slo-blo" style as opposed to Fast-acting
A fast-acting fuse will look like a single strand of wire ( maybe wiggly looking) ..A Slo-blo will have an element in it and a spring
Posted on Apr 11, 2009
Let's distill this down to its simplist configuration. FM source, stereo.
BTW, a search for NAD 440 only brings up a C440 >>>Tuner<<, no receivers. Are you sure about that model number? The only receiver model numbers with x40 on the NAD website are the C340 and C740, neither of which has a link to a manual (go figure). I have the C740 manual, so I'll use it for a loose reference.
If it still does what you're describing in a basic configuration and the volume control seems to affect it like you belatedly mentioned, I'd suspect a noisy volume control or some other control in the receiver (like a rarely used Tape Monitor switch) that is always there in the circuit but may have oxidized contacts and responds sometimes to burn-through.
Set the volume at a medium setting and repeatedly operate every switch, knob and button (one at a time) to gauge its effects on the sound. You may find one is the culprit. Then it's a matter of accessing it for a shot of contact cleaner.
If you have jumpers between Pre Out and Main In, it might be a good idea to reseat them, too.
Posted on Mar 24, 2010
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