NAD C372 - 30 seconds of static on startup. What gives?

[bkevind]

As you might have surmised from the subject, I have an aging NAD C372 integrated amp.  I use it to feed a pair of Forte II.

 

I'm quite happy with the sound / performance.  However on initial power up, lately I have been getting about 30 seconds of static/white noise.  Then it goes away and all is well.  

 

It's not the pot, or the tone controls.  Well maybe it's the pot but the symptoms don't add up.  I think it's in the pre-amp section.  For a short time I tried the C372 in bridged mode, paired with my C272 amp also bridged, and the noise happened then also.  I have tried different inputs with the same result.

 

Any ideas what might cause this?  

 

[geoff.]

It is the speaker relays.

 

Very common problem with many amps after time.

 

If I “crank it” right after power-on it resolves itself sooner.

 

I have three NAD 372s, one of them does the same thing. Always the right channel.

 

Now that I am running LaScalas I have no need to bridge the amps and am using only one amp. I flipped a coin and picked one of the amps that works fine.

 

There are many posts about fixing this, one even suggests a better relay for DIYers. I will be going tubes before I spend another dollar on SS though!

[CECAA850]

42 minutes ago, geoff. said:

There are many posts about fixing this, one even suggests a better relay for DIYers.

If there's a cap that powers the relay that could be your culprit.

[bkevind]

Thank you!  My google-fu was weak.

[CECAA850]

11 minutes ago, bkevind said:

Thank you!  My google-fu was weak.

The only reason I suggested that was that I had a similar issue with an old carver amp that I had.

[bkevind]

Once upon a time I actually used to troubleshoot and fix things BEFORE asking.  I've become so lazy!  I don't even have a multimeter anymore, or even a decent soldering setup.