Tube dampers/coolers effect on preamp sound?

Hi Rmcfee

I would say it would depend on a lot of things. What was the piece of equipment the dampers were used in? What kind of damper was employed? There are many kinds now. From silicone rings to brass rings with a ground wire.

I've used silicone rings and Herbie's tube dampers on the preamp tubes of my amp and I had the same results as Lowrider.

I am using a Joule Electra OBS-1 which has 6 tubes in the preamp part and more in the power supply but I wouldn't think that they would affect sound (I could be wrong).
I think of old Fender Teles with microphonic bridge pickups- the microphonics add a nice part of the tone but once it gets loud they screech and are a problem.
Maybe damping a tube (even if it is not noticably microphonic) could take something away from the sound.
And yes,I know, tubes are not electric guitar pickups.

My experience in my Jadis tubed preamps (using Tubesox, Top Hats, Vintage Tube Service's brass dampers (the best of the ones I tried) and Mapleshade dampers) has been that the better tube dampers take away a little bit of that tube warmth but give a bit more focus and clarity to the sound. This would be consistent with lowering the tube microphonics, getting rid of a small amount of distortion. Given the commparatively inexpensive choices available to you with the Herbies and Audio Research dampers, you might just want to experiment and see if you like the sound better with or without.

All tubes are at least a little microphonic; if you don't believe it, try a Herbies tube damper on a supposedly non-microphonic tube like a Military grade 6SN7 or 12AX7.

My experience is that tube dampers are essential. They can improve low level resolution, microdynamics, and allow higher volumes before distortion limits the volume at which you're comfortable. One thing I've found is that it's important to damp the tubes, but not to add mass that can store vibrational energy and then release it. Specifically, I recommend avoiding those tube damping rings that ARC supplies with their preamp tubes. Substituting Herbies Ultrasonic tube dampers on my ARC REF3 preamp eliminated a smearing quality compared with the ARC o-ring dampers. I mentioned this to ARC when I ordered tube replacements.

I do use very thin o-rings on the brass bases of my Kronzilla T1610 tubes. I find that four of these (1/16" thick and 3-1/2" diameter) made a surprising improvement in the sound, with instruments sounding more like solid and independent sources. Interestingly, when I tried putting those thin o-rings (rated to 450F) on the glass of the tubes, they start to smear the sound. For the glass envelopes, I use three Herbies tube dampers per tube.

There's lots of different types of dampers out there. I'd appreciate the input of those who have compared the Herbies dampers with other designs. One more thing, I've found that damping speaker cables also provides improvements.