[cjr888]

OK so we have items like the HALO dampers, and we also have items like the Pearl Coolers.  In addition, the Pearl's mention that they do some some dampening with the new carbon fibre sleeve to reduce microphony.

So the question -- who's tried both?  What are you using now and why?

[kennethlhc]

I have both, but my Pearls are older metallic type.  I'm using the Halo's as I found the Pearls didn't "improve" the sound, also tried the Pearl in a guitar amp which always turn tubes into microphonic after a while, the Pearl couldn't help.

For the Hal-o, you may control the amount of damping by slight stretch or compress the ring.  Too much damping will make your system sounds lifeless.

[MaxCast]

I've use the Herbies tube dampers and find it a great tweek for $10 a tube.  I use two on a foreplay.  They do help dampen microphonics.  These and good damping devises are a must for tube equipment, IMHO.

[KKM]

The primary function of the Pearl's is to cool the tubes and extend the life, works great if your tubes aren't microphonic. There's extensive literature on this at:

http://www.partsconnexion.com/resources/tubes/pearl_tube_coolers.pdf

Also Pearl has what's call Iso-Sockets that's suppose to eliminate microphonics, only used for preamp tubes w/ 9pins, kinda expensive, about $27.