Question about NAD C340 Integrated Amplifier

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NAD C340 has lost ability to switch between inputs

I have a NAD C340 that can't switch between inputs. All inputs are active at all times. I took to high end shop to have it repaired. ALthough they aren't a NAD repair outfit they do work on high end gear. They switched out the Micro chip AND the switching chip to no avail. They were all stumped. Am i stuck with just a power amp now?

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Re: NAD C340 has lost ability to switch between inputs

I have the same problem which started about a month ago and seems to be getting worse. I also noticed today, that 1 channel is significantly louder than the other - fault in the pre-amp stage, as feeding the power stage directly gives balanced, albeit extremely loud sound! Looking on eBay, I found someone else selling an amp with both problems. It would nice to think that NAD would acknowledge a design flaw, and fix for free, but my amp is 5 year old.

Posted on Sep 25, 2007

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Re: NAD C340 has lost ability to switch between inputs


sounds to me like they have used a chip to switch between the inputs and not relay's?

If that's the problem, only solution is to find someone to replace the chip. Often denon and cambridge use this kind of 'easy' and cheap work around remote controlled input selection.
In several of the nad's i have repaired, they used relays, so i will bee surprised if nad use chips also?.

best regards michael miguelovitch

Posted on Nov 27, 2007

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Re: NAD C340 has lost ability to switch between inputs

By mentioning "All inputs are active at all times." are you saying that all INPUTS lights are lit up at the same time? Or is it that you select a particular input option - say TAPE, and while the TAPE indicator Light gets lit, there is no sound coming from the speakers? In most Amplifiers, Input selections are routed through a couple of Relays. So, over time, the contacts of the Relay get dirty and signal does pass across. I suggest that you ask the Tech Store guys to have a look at the Switching Relays, and if suspect, replace.

Posted on Jul 16, 2007

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Register and download the manual for free at

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Hi There,

In a sound system there is an input selector switch which just connects the input socket you want to use to the "common" amplifier electronics inside...You say that the CD is fine so in this case it must be a faulty selector switch or broken copper tracks or wires inside the chassis electronics which connect those inputs.. through the selector switch to the amplifier circuitry.

The fault lies between the selector switch and the input sockets that dont work.....Not the CD one of course... thats fine..

Cheers From YUBEUT

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