tube damper help

Okay, no kidding. The black o-rings at the hardware store (take a tube along to get the right size) have never melted on me. Ever. But I use them only on small tubes such as 12AX7s and 6922s and should have said not to try them on power output tubes like El34s, 6550s, KT88s or anything else that runs really hot. My mistake.

Like Dopogue, I use silicone O-rings, but I purchased them online where I could be sure I got a formulation that would take the heat. They're available very cheaply and in my experience work as well as the Herbie's, the only others I've tried.

What effect they have is, like most things audio, dependent on the situation. I find they make more difference on octal tubes than 9-pin miniatures, and that they make more difference in units that have top mounted tubes rather than the tubes enclosed within the chassis. In some instances, they've made no discernible difference at all, but I still use them because it makes me feel better.

:-)

David

Another vote for Herbies!

I use 3 mm white Marigo VTS dots under all of my tubes.

'black' may be OK for low power tubes. Black may be Viton, Buna 'n' and many others, including just plain rubber.(neoprene?)
Silicon (red?) has silicon oil in it which can migrate out and make a real mess, on higher powered tubes. If i had tubes and thought damping would help, and it may in certain feedback situations, I'd use EP, which will take more heat, is inert to many (certainly around the house) chemicals and is not too soft. EP stands for Ethylene Propolene.
If all you care about is maximum hi-temp use, try Kalrez. Good luck finding this at the local emporium, but I think that 500f should be good enough for most power tubes, too.
http://www.mcnallyinstitute.com/04-html/4-9.html