"Stewart Pinkerton" wrote in message
...
On Sat, 27 Nov 2004 04:48:43 +1100, Patrick Turner
wrote:



Mike Gilmour wrote:

"mike" wrote in message
.net...
Thank you to all for the info.
I know Audio Research uses them on all their products.
just curious
Thanks again
Mike M

Try it for yourself. Wind 20 turns of teflon tape directly around a
tube
and listen. Bill Beard used to do that I believe on signal valves.
Personally I'd prefer to select less microphonic signal valves. The
metal
vaned coolers however do IMO extend power valve life considerably and if
you
ground the coolers on signal valves it acts a bit like shielding. You
don't
see screening cans around much nowadays. The very slight hum on my
amps
went when I grounded the signal valve coolers.

I'm waiting for the flak ......... ;-)

I don't see a need for tube dampers.
Pick non microphonic tubes, and all will be well.

Besides, some micro tubes would be still micro
with dampers, since the elements sway around if the mica discs are loose.

They used to place tubes in aircraft in tight fitting metal surrounds in
an
effort to keep
them cool, with an air flow past the metal.
The planes flew so fast the air flow was hot, so they had to use
refrigeration
to keep them cool.
That made the planes heavy, since gridges are that way,
and so some bright spark said let's use solid state.

Case closed.....................

--

Stewart Pinkerton | Music is Art - Audio is Engineering

If aircraft had kept tubes maybe their sound systems wouldn't suck ;-)