Several months ago I mentioned the use of some vinyl coated lead rings to damp the 300Bs on the Bee Pre. I also mentioned the use of some Sorbothane hemispheres under the corners of the base. Steve Herbelin saw the thread and generously offered some Herbie's tube dampers and Tenderfeet for me to test. I have been remiss in commenting on these offerings until now.
The Herbie's on 300Bs seem to do a bit better job of killing the high frequency component of the ringing caused by chassis borne vibration and microphony. They will also work on very hot tubes due to the high temp tolerance materials used. In the very unusual case of the BeePre where the bulb temp of the 300B is much lower than usual the vinyl clad lead rings have held up well with several months' use. And I have found them to be a bit more effective in reducing the length of the resonance decay, though as I said before the Herbie's seem to edge them out in the high frequency damping. For me the lead rings have a slight overall advantage due to the reduced decay time of the mid and lower frequency vibrations. My conclusion here is that I will probably stay with the lead rings on my BeePre, but the Herbie's show some real potential for use on tubes notorious for a dominant HF component in their resonance, like the 6DJ8 types.
The Sorbothane feet I bought were quite effective in stopping vibration coming up through the shelf into the wood base. But as Steve suggested, after several months they have collapsed to about half of their original compressed height and in the process the preamp does not sit quite level. And as discussed before they stick to the shelves and tend to pull off the wood base when you pick up the preamp. The Tenderfeet seem just as effective, look much nicer and don't stick. I think they work very well with the Bee Pre and ought to work equally well with other vibration sensitive gear.
Thanks so much to Steve for the opportunity to try these products out!
The Herbie's on 300Bs seem to do a bit better job of killing the high frequency component of the ringing caused by chassis borne vibration and microphony. They will also work on very hot tubes due to the high temp tolerance materials used. In the very unusual case of the BeePre where the bulb temp of the 300B is much lower than usual the vinyl clad lead rings have held up well with several months' use. And I have found them to be a bit more effective in reducing the length of the resonance decay, though as I said before the Herbie's seem to edge them out in the high frequency damping. For me the lead rings have a slight overall advantage due to the reduced decay time of the mid and lower frequency vibrations. My conclusion here is that I will probably stay with the lead rings on my BeePre, but the Herbie's show some real potential for use on tubes notorious for a dominant HF component in their resonance, like the 6DJ8 types.
The Sorbothane feet I bought were quite effective in stopping vibration coming up through the shelf into the wood base. But as Steve suggested, after several months they have collapsed to about half of their original compressed height and in the process the preamp does not sit quite level. And as discussed before they stick to the shelves and tend to pull off the wood base when you pick up the preamp. The Tenderfeet seem just as effective, look much nicer and don't stick. I think they work very well with the Bee Pre and ought to work equally well with other vibration sensitive gear.
Thanks so much to Steve for the opportunity to try these products out!
