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pre65 14th September 2013 03:09 PM

Pre3 problem.
 
My Pre3 has a problem.:(

I have a noise on one channel, it's regular, but intermittent. I say intermittent but the gaps between are very small. A bit like motorboating but not.:confused:

When the noise appears (seems to need a little while to start) the volume control (shunted alps) and selector switch have no effect, even mute.

I did change the two 0.1uf coupling caps but that made no difference.

Help.:o

Richard 14th September 2013 05:05 PM

Re: Pre3 problem.
 
Hi Philip,

Sounds like a noisy valve, have you swapped them over to check or popped in a new one?

Pre3 runs them quite hard compared with a lot of other gear (several whole mA!) and Gerry B and I have both had noisy ECC82, the supplied JJs in particular.

I think they would be fine in gentler applications but perhaps the extra heat gets to them. We made up a good pair between ours and that was fine and I use some nos Mazda/Thorn which are good and have been in 2 or 3 years now :thumbsup:

pre65 14th September 2013 07:54 PM

Re: Pre3 problem.
 
I did try swapping the two valves around but the noise stayed put.:(

I'll see if I can find the original valves and try them again.

pre65 14th September 2013 09:09 PM

Re: Pre3 problem.
 
I found the two ECC82 and plugged them in, and the noisy channel was noisy as soon as I switched on.:eek:

I wiggled the valve a bit and it's gone quiet for now. Will see how it responds after 30 mins or so.

I was using GE 5814wa up till today.:)

pre65 16th September 2013 05:39 PM

Re: Pre3 problem.
 
Touch wood ( puts finger on bonce ;)) the pre3 is still noise free.:thumbsup:

Richard 16th September 2013 05:46 PM

Re: Pre3 problem.
 
Great stuff, what do you think it was, noisy valve, dusty socket, or is it worth resoldering the bases to the pcb do you reckon?

pre65 16th September 2013 05:53 PM

Re: Pre3 problem.
 
I'm more inclined to blame the socket.

I re-soldered the valve bases a while ago when the problem first occurred.

Perhaps I will re-try the 5814wa at a later date.

Greg. 16th September 2013 10:19 PM

Re: Pre3 problem.
 
Glad you've got it sorted, our Philip :thumbsup:

pre65 17th September 2013 11:14 AM

Re: Pre3 problem.
 
Quote:

Originally Posted by Greg. (Post 80204)
Glad you've got it sorted, our Philip :thumbsup:

Cheers Greg.:)

I've tried several times to build a better pre-amp than pre3 but although I have had successes I always end up coming back to pre3.:cool:

Ali Tait 17th September 2013 06:15 PM

Re: Pre3 problem.
 
The Aikido not better then!


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