Traynor YBA-1-ish amp - PTP - Static/Ghost noise problem

[infiniteposse]

Hi all-

A few months back I purchased what may or may not be a Traynor YBA-1 prototype. Over the years many parts have been changed, so I'm zero concerned about authenticity, I just want it to run as well as possible. I've done work on it since I got it and cleaned it up fairly well. There's one lingering problem I'm stumped on though and I'd really appreciate some ears.

The noise that happens is a sort of random ghost click. It ramps up the longer the amp is on. Thus far I've tried preamp tube swaps to no avail and I've also replaced one of the 12ax7 tube sockets, but this also didn't stop the problem.

The amp had been recapped before I purchased it, so I have not personally replaced filter caps. It had some orange drops that I upgraded to Sozo's, which is a personal preference. I also went through and cleaned up any suspect soldering to try and make things more reliable.

I've uploaded a noise example to my studio's bandcamp page so that you guys could take a listen. It really gets going around 2:20. Here the link to the audio: http://mysterymachinestudio.bandcamp.co ... idle-noise

I'm open to all suggestions about how to attack the problem.

Also, here's a link to photo's of the amps guts pre-me working on it: http://s18.photobucket.com/albums/b149/ ... r%20YBA-1/

[IMG765]http://i18.photobucket.com/albums/b149/ ... roto11.jpg[/img]

[Cliff Schecht]

Electrolytic caps of unknown quality/condition, wax impregnated PIO cap and ANCIENT CC resistors. There's a lot that could be wrong with something like this. I usually don't hesitate to gut something like this and put in something that I want to build with known, working ancient components.

[selloutrr]

I would replace that waxy looking filter cap in the top of the pic.

clean and retension your tube sockets and spray fader lube in your tone controls.

see if it is any better.

The resistors are suspect.

If you have an amp probe you should listen to the circuit and isolate the noise.

[Andy Le Blanc]

second replacing the wax cap, Its a build up and discharge I'd check all the
coupling caps for DC leak, and give the old tube sockets a good look for
any arc/burn, I've had a few wtf moments with old gear around old phenolic sockets.

Leave the thing running on the bench until it really gets going and then start
poking around looking at voltages, the meter probe might turn it off/on.

[ampdoc1]

It sounds like heat is causing the problem. I'd suggest you get a can of computer dust remover. Turn it upside down (this lets the cold freon come out instead of air) then spray the individual components one by one, once the amp starts to "tick".

Quick, easy and cheap way to test for thermal problems.

a'doc1

[infiniteposse]

Excellent advice all. Thanks very much. I'll move forward with these suggestions and see where I end up.

Thanks again.