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For a few months now the gain channel on my 2 year old SIIIv6 has had a horrible bacon frying noise. Channel is unusable. Tubes have been replaced and almost all caps that I think might be in the mix have also been replaced. Still no better. I have been using the clean channel only which sounds fine. Do you have any suggestions of what I should replace next? Or can you suggest a good amp repair guy in the Oakville area.

Thanks

Is it a crackling/farting sound only when you hit notes or chords? or is it a constant sound even when not playing?
If it is only when playing, is the amp on the speaker cab? Try placing the amp on the floor away from the speaker. Does the sound go away? If so it may be a loose connection or cold solder joint. You can chopstick inside with a plastic pen and see if you find the sound when tapping or moving things inside.

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Les

http://www.soundclick.com/unimind

Thanks Les, noise problem is all the time.

Have you tried the chopsticking? Any change in the sound when doing that? Can you post a sound clip of the noise? I am just guessing here you really need someone with more expertise to see what their thoughts are. Just thought I would try to help.

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Les

http://www.soundclick.com/unimind

Usually that's a preamp tube problem. However, as you're saying that you've tried swapping tubes, then it's more likely a bad solder joint or a carbon comp resistor gone bad.

I know reliable amp repair guys in the GTA, but not Mississauga/Oakville side. I'm also pretty much out of action for the time being with a broken leg.

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Great tones come in small glass jars!

Thanks guys. Spend about an hour last night with a chop stick moving everything but no change. Again the clean channel does not have the same problem. So it looks like a bad component in the pre-amp stage. I was mentioned to look at resistors. Just wondering the best place to start? V2? plate resistor?

Start by trying to find whereabouts in the preamp the noise is getting in. So pull out the first preamp tube. Is the noise still there? If it is, then pull out the second tube. By then the noise should be gone. This test will giv you some clues where the problem lies. Then put the tubes back and start tapping components and solder joints around the suspect part of the amp, to see what happens. You may need to reflow some solder joints or even replace resistors.

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Great tones come in small glass jars!

I have pulled Vi and the problem is still there. When I turn the master volume up the noise problem also goes up so since the master volume is between V2 and V3 I am sure the problem is around V2. I will try resoldering all the components around V2 and if this does not fix it I will start replacing resistors.

Thanks

Forgot to post that I fixed the noise problem. C3 (500pf) was it. All good now. thanks