Do tube dampers improve sound?

I'm trying Herbies Audio Labs Hal-o dampers the Black Nylatrons on my Aesthetix Calypso as I write... and so far so good. They quiet down the pre amp somewhat, unless I'm hearing things (that are not there) or is that... NOT hearing things that were there?! Anyway, I feel that they are a good value, so far. Now to try them on the Rhea phono amp.
Happy Listening!

Hey Roger,
Tube dampeners make a noticeable improvement in performance. They tighten the bass, clear up the overall sound, and reduce microphonics. Definitely worth it, and they are cheap. Used them on my AES/Cary pre with great results.
So what is up with your system. I see you have a Dynaco tube pre.
Mike

I guess if I have to strain to attempt to hear a difference
I write it off as a bad investment. I put Herbies tube Dampers on my entire system (all tubed at that time) and failed to hear any improvement. The other thing I noticed is that the dampers used on my kt 90's got sloppy with use.
They are sagging on the tube and not really holding onto the tube. On the other hand herbies grungebuster is the best tweak I have ever tried. For 16.00 it made a large improvement in the sound of my cd's.

I used the Herbies dampers too on my tube integrated and have to say I could'nt hear a difference. Interestingly, HiFi News here in the UK, did a technical report on a number of tube dampers, including the pearl ones, though they are coolers too of course, in this months edition. They checked for microphony with and without the rings and found very little difference. Does'nt mean they are right of course, accurately measuring these things is'nt easy.