valve damping......

DavidF

DavidF

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"Valve amps can be very microphonic, so some damping materials can change the sound ................."

I hope Rob deosn't mind being quoted.

Haing just got my van insurance bit cheaper (for a moment) feeling rash!!

Can anyone recomend (valve) damping sleeves....or materials....that won't set my house on fire?

:eek:







tia




David
 
I've used Golden Dragon tube rings in the past with very good effect. Also used something which looked very much like a round heatsink (Pearl Coolers, or something like that) which made precisely nil difference.
 
I use EAT dampers on my input valves - a bit pricey at £15 each (I need 4) but well worth the improvement.

I also tried Herbie's Audio Lab damper on my output valves. Big change in the sound, but I didn't like it - things got very tight and over-controlled. I'm not knocking them, they certainly had a very noticeable effect, it just wasn't to my taste.
 
I've previously used these on small preamp valves: ebay item 370184383674.

My old amp (Copland CTA401) used to make an very audible 'clunnnnnnnnng' noise through the speakers when I rotated the input selector knob from one input to the next. Couldn't say for sure whether the quality of the output when music was playing changed a great deal with the dampers, but they definitely cut down on the 'clunnnnnnnnng'-ing!

Dodgy microphonic old brimar ecc82/83's were to blame IIRC, but they sounded lovely compared to the Golden Dragons they replaced.:D

I may have a few spare dampers hanging about in a drawer somewhere as I'm sure I had some left when I sold on that particular amp.....
 
Heat Shrink.

Works a treat on small signal tubes. Use a high temperature type and only cover about a third of the glass. You can get large diameter HS from RS but you might need to stretch it out a little with some long nose pliers.
Just slip it over the valve and let the heat produced do the rest.

No need to spend silly money on audiophile rubber.

Here's one I prepared earlier:


IMGP0821.jpg
 
any one tried


Babbitt putty, a high-temperature material (978°F) similar to Mortite, can be used effectively on vacuum tubes and yields excellent sonic results, but exudes an offensive odor.
 
DavidF said:
but exudes an offensive odor[/I].
Click to expand...

I think that bit would put me off :D.

Use what Rob suggested, or if I can find my spare dampers you have 'em for nowt - they were only a few quid anyway. I'll have a look for them tonight when I get home.
 
Anyone tried dampers on 300B tubes to any improvement, and if so what? :-)
 
I think Zanash used some high temperature O rings he bought on Ebay.

I think these are ideal on pre-amp tubes too, and have been meaning to get some for a while.
 
I'm not so keen on covering too much of the glass, after all it's how the tube dissapates heat.

The O-rings therefore look better than the shrink-wrap to me.
 
Hi Larkrise

Haven't tried it.

I have seen specialist O ring type devices for 300B's, but have always balked at the cost (seemed very high for high temp rubber bits and wire).

Have you done the pre-amp tubes already? - IME this is an area more prone to Microphony.
 
Hi Bottleneck - yes have rings on the smaller tubes but have never seen damping on 300B's so wondered if anyone had tried it.
 

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