I do have a few little problems with my valve sockets. They are made by Yamamoto Onkyo Kogei from Japan. They are very highly regarded and in construction, you could not fault them. They are hewn out of a block of solid Teflon, and have either gold or silver-plated phosphoured bronze contacts. They are anti-vibration and are easy to wire up. Here (
http://www.triodes.nl/en-us/dept_24.html) are the gold ones, but mine are silver plated. These are around $40 each!
What does happen over time though, is the little contacts lose tension and fail to grip the pins correctly. I have to reset them. This is a reasonably well-known problem with the Yamamoto sockets. I am not aware if the gold-plated contacts are better in this regard.
I went to a tobacconist bought a very narrow nylon brush and some pipe cleaners (not the highly absorbant ones as they are prone to shedding). I use Caig Deoxit to clean the contacts, and then apply a little high temperature ProGold. I then use a jeweler's screwdriver to bend the contacts towards each other so they grip the pins better. I use a number of correctly sized drill bits (I have measured these with vernier calipers and found ones the same size as the various tube pins). I use the drill bit as a guide, and bend the contacts carefully until they make good contact.
I just clean the tube pins with Deoxit and add a drop of ProGold. One has to be careful of using abrasives (steel wool, Flitz) on plated metals. If the pins were solid metal, I imagine it would be fine; but I think most tube pins are plated metals.
If you read what Caig have to say, you might not use an abrasive. That includes a pencil eraser - some have recommended that an eraser is OK. Here are two quotes from Caig.
"Do not use an eraser - ANY TYPE OF ERASER - to clean contacts. Erasers are highly abrasive and will remove the precious metal plating. Further, the glue in erasers leave behind a film that is extremely difficult to remove and can later cause intermittents. Also, rubbing an eraser back and forth across contacts can be a potential static generator which could ultimately short out the system."
Question:
How do I clean tubes that go into the pre-amp?
Answer:
If the plated surface has oxidized, apply DeoxIT initially. Remove the contaminants that have been lifted by the DeoxIT with a lint-free swab, if feasible. Once you're satisfied the surface is clean, apply ProGold GxL, which has been specifically formulated for high temperatures. Maintain thereafter with ProGold GxL.
I've definitely thought about getting a Dremel as that seems like fun - and it's a very cool tool. I requested a sample of Flitz ($5) and they sent me a tube and a couple of sachets - I plan to clean the blades on the power cord plugs, not the tube pins.
Regards,
Geoff