From dsalley@pacbell.net Fri Oct 19 19:56:42 2007
Subject:Re: Tube dampers?

Do a Google search on "Why use tube dampers?"

You'll get a lot of forum responders in various tube using sub groups
that will say how they feel about them and their use. It's pretty rare
to read a negative opinion and pretty much all talk that is derisive
about them is from folks who don't use them and think they are a fantasy.

You'll also get links to many manufacturers of them and you can read
their extolling the virtues of their use, especially on pre-amp tubes,
like 12AX7/ECC83/ECC803 and the like. Reading the claims is OK, but
trying them yourself is where it's at.

They stop microphonic noise coming from either the tubes own
microphnics and microphonics produced by vibration of what you are
using them in. Combo amps, like most all Leslies and Leslie type
speakers produce a lot of microphonic producing vibration. Spinning
rotors (almost always slightly out of balance), booming speakers (any
12" or 15" woofer type speaker) at high volumes and low frequencies
produce a lot of sub and microphonic vibration. This is carried right
to the pre-amp where the tube is attached to it's socket and the
socket attached to the pre-amp chassis itself and that chassis
attached to the interior of the cabinet. A nice pathway for vibration.

To prove it or not to yourself (the only person that really matters if
there is a debate about their worthiness), get some of the cheap ones
from Sandy and slap them on your pre-amp tube(s).

Crank up your amp/speaker(s) sound level big time, bury your
expression pedal to as high as you can handle it and play a big fat
chord with your rotors on high speed, if you have them. Then take the
dampers off and repeat. With the dampers on, you should hear a
noticeably richer sound, free of any microphonic artifacts.

Then try the experiment again, but this time play nothing, no sound
input. Toggle your rotary speeds to all states, (again, if you have
"Live" rotors). With dampening you should hear absolutely nothing but
the air being moved by your rotors. You may have some artifacts of
noise from your instrument of choice, but not vibration induced
microphonics coming from your amp/speaker(s) pre-amp tube.

I use the Herbie's Audio brand called BlackBery HAL-O 9 and the Sandy
Photo (eBay) generic brand. Sandy has expensive ones too called
SoniKLEER. The 2 different kinds that I have work equally well. With
BlackBery HAL-O 9 dampers you just use 1 per tube. With the Sandyphoto
dampers, you use 2 per tube. My choice of gear H/S XK-3-Leslie 3300)
uses just single or double pre-amp tubes only. Your gear may be a lot
different.

There's even another debate about dampers. Do they work on power
tubes? Some say not at all, "Impossible!" Some say they add to even
more quality and clarity of sound when used on some power tubes. I
can't answer that one for myself because my gear doesn't have any
power tubes.

There's some really exotic looking dampers too that can be extremely
expensive. I think that may be where they lose people and credibility.
Goggle around a bit and check it out.

Let yourself be the judge for a very small investment. Try them on
your pre-amp tube(s) and listen.

Sandyphoto (8 for $9) : http://tinyurl.com/3x4l7e

Herbie's ($10 each) : http://herbiesaudiolab.home.att.net/special.htm

XKDave

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--- In CloneWheel@yahoogroups.com, "jblann1" wrote:
>
> I saw another post about using tube dampers... what is that, and why
> would one use it?
>