deoxit? NO!

[bob p]

Thanks for posting, Steve.

One of the projects that I've had on my long list of things that never seem to get accomplished is the switching MOSFET for speaker protection and anti-thumping. I have a number of amps that I rotate through home audio duty, some of which thump worse than others. On some amps I've already added relay-based anti-thump circuits, but I'd rather not modify every SS amp that I own, and I'd prefer to avoid mechanical switching for the reasons you cited. To avoid that burden of modding every amp, I've thought about building an independent "speaker protection" box that would go between speaker and amp to handle the turn-off thumps, monitor for DC output, etc. The trick is going to be making it function transparently.

[soundguruman]

because, when I come here I always mange to fix something.
In gratitude to the many helpful guys here, I offer the following:

As I'm sure that it is obvious to many here, and now to me,
using contact cleaners that have conditioners and contact/conductivity enhancers can be deadly to your tube amp.

after fretting over some ugly red plate issues and other cross connection problems in my 66 fender twin it, occurred to me that the deoxit spray that I used to clean tube sockets and bias pots might be working better than desired. The oily reside covering all these pots might be providing a signal path and leading me to believe that my power trans or OT trans or both might be failing or failed entirely.
I was just about to begin a total rebuild when I decided a clean surface might be a better starting point.
I went to pepboys and bought some CRC brake clean ( fast drying oil and grease remover with no residue, basically acetone) and cleaned all relevant contacts .

ta da!! amp works like new! better than it has in ages.
proving once again the old adages;

1: there are very few things in life that a little soap and water won't cure.
2: 90% of the time the problem is sitting in front of the amp.

note:
be cautious!
some of these cleaning sprays can be highly flammable and should not be used indoors. (do not power up until compound has completely evaporated)
Alternatively;
make sure the can says dielectric and non flammable, and those so marked are harmful/deadly if inhaled for any length of time.

Spraying cleaner into tube sockets is a really bad idea.
Trying to make up for the fact that the plating on the socket receptacles is bad / burned off...
I replace the sockets, and won't pretend that "cleaner" is going to fix the problem.
Granted, cleaning will be a fix temporarily...but the problem comes back over time.
Caig does make a deoxit, specifically for high temperature. But it's still not for tube sockets.

Brake Clean? That destroys many types of plastic. Denatured alcohol is cheaper and overall, safer, for use on circuits.
But no matter what type, the vapors are harmful, and flammable. Use with ventilation, for sure.

And while you are at it, inspect the tube PINS. If the pins are black and burned, it causes excessive heating, wrecks the socket plating, electrical conductivity fails. You can wreck a new socket quick with an old fried tube.
BETTER to replace a tube with blackened pins, if you can't polish off the carbon. If the plating is bad, replace the tube.

"ta da!! amp works like new! better than it has in ages."
Temporarily...until the spots where the plating is worn off start to oxidize again.