Bottlehead Forum
Bottlehead Kits => BeePre => Topic started by: Doc B. on July 26, 2013, 10:52:38 AM
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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!
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Doc, I just looked under a component that was using the Sorbo feet and yup they are compressed. Soon, I might an alternative such as the Tenderfeet. When looking at such products, Herbies is reasonably priced.
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Thanks for the report Dan. I found that a combo of the herbies dampeners and the lead weights to work well.
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I have been using this combo for awhile now. Very happy with it!
Debra
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Yeah I just put the Herbie's on along with the lead on my BeePre, since it will be in a system running headphones tomorrow and I want to kill as much vibration induced noise as possible. Not sure I'm getting a combined effect compared to just one or the other alone, but it's certainly no worse.
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I know what you mean Dan. I tried them both individually and found the weights to make a greater overall reduction but the Herbies help above what the weights can do alone. I just ordered a pair of the guitar amp style (for extreme vibration) for the 6B4G's.
I've found that the more I reduce the microphany, the better the overall sound is.
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Hi Aaron. did the new Guitar tube damper make difference over the stock Herbie"s. Also cheaper in price, no?
Dennis
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Hi Dennis,
They were of a different size and I can't directly compare them to the UltraSonics I already have. I plan on ordering a pair in the guitar version and post results at a later time.
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Here's another alternative that just showed up recently on the 'bay. I'm going to grab one and I'll post as to their effectiveness. Unfortunately, I don't have anything to compare them to though.
My amp is on the verge of coming to life so I'll have some listening time before they arrive, so some comparison at least. I'm going to pick up a set of Herbie's tenderfeet too.
http://www.ebay.com/itm/4-DuoDAMP-300BTUBE-AMP-DAMPERS-300-B-LARGE-ST-TUBES-/370878996772?pt=Vintage_Electronics_R2&hash=item565a1c6124
Aural Robert.
... and what about stairs? ...
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Thanks for the link. I always am interested in new products and ideas.
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I sold an old Solid Steel 3.5 stand today, and so had to take my Merrill TT off of one of the shelves that I put between my Target wall stand and the TT. Coupling the shelf to the stand were 4 Herbie's hard Isoballs. They fit into these metal discs with compliant material undertneath. Taking the shaggy dog story to its illogical conclusion, I noticed that the Isoball/cup thing would give me significantly more height under my 2A3 Stereomour. Hey! Maybe I don't have to sell those Mundorf Supreme Silver-Gold 3.3 uf caps after all. With that extra height, I should be able to get enough airflow under there so that the 55C rating on the Mundorf caps won't be too big of a problem. So, I ripped the Tenderfeet off of the amp base, and slipped the Isoball thingies under the Stereomour instead.
Damnedest thing happened. Tighter definition, more obvious articulation, just about everything is crisper (Here come the flames.) My 14 year-old son Josh just came in after being chased by a wasp, sat down for an episode of Burn Notice on Netflix, and said (unsolicited) "everything is more crispier (sic). Out of the mouths of babes comes . . . (oatmeal?) No really, we both noticed it right away.
Hey, that wasn't my intention. I just wanted some more airflow.
Is this a DBT-free zone?