Tube amp - tube socket problem


Hi fellow tube amp owners. Four months back I bought a used Primaluna Prologue 2 which I really enjoy listening to. I'm the 3rd owner and it was built in 2004. I have a problem with one of the preamp tube sockets. One day I was very lightly dusting the top while it was running. I barely touched the tubes, and I heard a loud pop/crackling noise. Turns out the left side 12ax7 socket is the culprit. In normal operation it's fine, no noise no problems. If I gently wiggle the tube it makes the noise. It then has to be returned to a precise position to return to normal. 

I contacted a local tech who said the sockets can become loose over time and/or get some contamination from the tube pins lodged down in there. He didn't seem too keen on working on it, but said he could try to clean it out. I wondered if there was a bad ground or short, so I opened it up and inspected all the solder joints involved with that socket and found nothing wrong. I don't really want to ship it to have it fixed if I can avoid it.  My main concern is that it could get worse overtime or lose some performance on that channel from not making good contact.

Any ideas? Has anyone had a similar issue? Thanks.
dtapo

Showing 1 response by millercarbon

Agree, tweak the pin pockets. There's also some very fine pipe cleaner type wires that can be used to clean inside. Had mine so long, forget where they came from. I would also try and find a wire, same gauge as the tube pins, to slide into each pin pocket individually to figure out which one is loose. If you have an old tube on hand to sacrifice a pin that would be the way to go.