Do tube dampers improve sound?

I have high efficiency speakers and SET system and tried dampeners and found them to restrain(soundstage shrank) my system.I took them off and am happier for it.They also took the air and spaciousness away i felt.

I use very heavy brass dampers from Vintage Tube Services on the four 6SN7s in my Rouge 99 preamp. I have switched them in and out and used them with a variety of 6SN7 types.

I can report a tremendous sonic benefit. Bass is dramatic both in depth and definition. The soundstage is defined. With the dampers, highs are pleasant, not harsh.

I won't use tubes without them.

I do have the Herbie Halo dampers on the small signal tubes in the Zeus power amp. I do not notice much of a difference there, however.

hocus pocus

There is a noticeable difference when using them with large power tubes (2A3/300B/etc), especially when direct-wired in SET configurations. The larger the tube, the more difference they make, in my experience. Whether or not you like that difference is obviously a matter of personal preference.

If you doubt the effect, put one around a slightly microphonic 6922 and listen to what happens. Hocus pocus, my hiney.

I find it makes a difference where you put them. Dampers seem to work best near the top of the tube, not in the middle. Hey, maybe that's where the "top hat" idea came from.

But thinking of the glass as a transmission line (or guitar string), this makes sense. You minimize reflections, and hence resonances by damping the ends, where refections occur. In fact, some of the spots in middle (or harmonic fraction thereof) could be null points and have no effect. Depends on the resonance mode, if fundamental or higher. Only way to damp them all is to do it at the top or bottom.