Pictures of wiring, ab763 reverb parts

[überfuzz]

Yeah, hopefully I'll pick up a thing or two. I told him that I started building amps around transformers gutted out of retired amps. That really got him started. He told me about his own overdrive stage and clean stage etc. Interesting stuff!

I'll report back asap.

[überfuzz]

I just phoned the amp tech. He said that he had checked it properly. There were nothing wrong but the wiring. Apparently he just shuffled around them and were able to reduce the noise. The noise were picked up by the input wire and possibly by the reverb to pot wire. He suggested a shielded wire from the input on the tremolo channel.

I'll test it myself and report back. Cheers for now!

[überfuzz]

Stop the presses. The noise is still there. I phoned the tech and told him about the present status. (After he tinkered with it.) He said that he thought he fixed it. Then I asked him how long he run it while checking the result. 'A minute or two.' ARGH! I told him that the noise starts after 4,5 minutes. Now he wants another go at it. Hmm...

I try to find the bad part using cooling spray.

[MWJB]

Pinning down noise can be frustrating & time consuming...you need to have the amp where you can leave it on for extended periods & be getting on with something else, whilst listening for noise.

This thread has got so long that it is hard to establish what you have done/not done, can you recap/review and start a new thread?

Use the stage isolation technique to deterimine whether a particular tube, or triode is responsible for the noise.

[überfuzz]

This thread has got so long that it is hard to establish what you have done/not done, can you recap/review and start a new thread?

Right, I could list the things I've done/checked so far here in this thread. Or as you say start a new thread... I'll get back on that later, haven't got the time now. Life outside calls upon me.

[überfuzz]

Update
Yesterday I wrote an exam in complex analysis. It vent quite well! Today I decided to have a go with this amp...

The amp
I started from scratch, shifting tubes around. When I shifted v1 and v2, behold, the noise shifted to the first channel... So I phoned the owner and told him about the bad tube. It turns out that he bought a batch of 6 JJ tubes of which 2 12ax7 were stillborn. Why JJs you might wonder, 'they were cheep'. He bought two new and thought he had 6 good tubes. Thats why he insisted it couldn't be the tubes.

Epilogue
Apparently I didn't check the tubes properly the first time around. (Oh don't mention it, I've all ready written, I MUST ALWAYS CHECK TUBES PROPERLY, a hundred times.) Furthermore, if anyone is reading this and is planning to buy tubes. There are one brand I would disregard.