You can always use a Mortite or Dennis Rope Caulk dime sized hat on 'em the top, too. Just let the tip poke out a bit.
I've used, or use them on hot running 6n1p's, rectifier, regulator and larger output tubes without a hitch.
The Herbies are decent deals at $9.95 a piece....but I think you can get a package of rope caulk for US$5.00 and it'll do thousands of tubes.
I use the Herbies (the 7, maybe it's called?) on my 6n1p's and 12ax7's...in
conjunctionwith the mortite top hatter. I want to hear the effect of the tube - not the microphony that often comes along with tube listening. When you damp those tubes real good, the audible difference between SS and tubes slims up quite a bit closer.
Of course, many enjoy the microphonic/euphoric effects - to each is own in life - my power to it, say I
The rope caulk does some off if you don't like their effects...harder to get off than a Herbie's Tube Damper will, tho. But cheaper - much.
