Tube dampers

Given that a device attached to the glass envelope is being asked to damp vibrations of the electrodes within, this is hardly surprising. But dissapointing nonetheless.
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I am very skeptical about tweaks of this nature, but, getting into the spirit of it, the above quote doesn't seem to me to be very sound (no pun intended).

The glass envelope, the electrodes and indeed the whole valve constitute a resonant structure. God knows how it resonates in a sound field. The sound must excite primarily the glass envelope, which is first in the firing-line. Some sound must penetrate the glass and excite the electrodes. The sound impinging on the glass and the electrodes must excite them to some extent, and the structure resonates according to its natural modes. If the glass is damped in some way, then it will respond less to the impinging sound field, and it will transmit less sound to the electrodes. The resonant structure will be to some extent more damped than it was before, and the electrodes will have less sound impinging on them to excite them. That is a multiple benefit: the structure is more damped, and part of it (the electodes) are less excited by direct sound and by the motion of the glass responding to the sound field.

So, as a person who knows practically nothing about it, I can only conclude that any changes damping rings make can only be beneficial. Whether the benefit is significant or audible, I have no idea. No-one here seems to feel strongly that it is.
 
DennyL said:
So, as a person who knows practically nothing about it, I can only conclude that any changes damping rings make can only be beneficial. Whether the benefit is significant or audible, I have no idea. No-one here seems to feel strongly that it is.
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They do look cool, though.
 
Hi Pete,

I've bought lots of tubes from Hotroxuk - fast, relaiable and good prices.

Yes I did fit the PIOs, in fact all the caps in the phono stage are upgraded. Silver mica in the EQ stage and high temp 5% electrlytic where absolutely essential.

My Pre amp uses an ECC88 which gives X30 gain before the output transformers. I have a tin full of ECC88s and many are microphonic...... and clearly less so with the shrink in place..... so I think this is one tweak with clearly audible benefits for little outlay. I'm sure the rings would produce a similar effect.

zanash said:
RobHolt....

just spotted the pics ...a couple of makers use heat shrink on there tubes, though the ones I've seen fit them higher up near the shoulder. Supposed to be quite good but the charge a lot more for them over the naked versions mesa boogies ! thats them see....

http://www.hotroxuk.com/store/erol.html


£26 pounds a throw ! The heatshrink looks quite thick maybe two layers !


Did you fit the paper in oil caps ?
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I've tried em on cheap modern tubes and they make a little difference to the sound - kinda calm it down a bit.
In my experience, good NOS or OS tubes like Kenrad, Tung Sol, and National Union don't have any decernable microphany - so I stick to these, they also sound a hell of a lot better.
The VT-231 Silvania's I have do suffer but these are just too 'alive' for me to use them for any length of time - nothing against the tube or manufacturer, just personal pref in my system.
 
I don't think anyone is claiming any more than you've heard, but a true test of microphony is get a rubber ended pencil and tap gently the valves with normal volume but no signal and see what happens!

If you've found valves that don't ring then thats great .....the rest of us mere mortals have to put up with cheap ones !



Rob.......

I fitted the same [?] pio's of russian origin to my dac ah ....with great results a very liquid and flowing sound!
 
I went with a set of the Herbie's Audio Labs dampers for my preamp and did notice a small but worthwhile improvement on the NOS valves - and for the asking price this represented better value than a cable change or other kind of tweak would have.
 
valves can be tested for microphony prior to purchase.

CvC provide this service on their premium range.

Getting a valve with lower microphonics is the solution I'd reccomend.
 
bottleneck said:
valves can be tested for microphony prior to purchase.

CvC provide this service on their premium range.

Getting a valve with lower microphonics is the solution I'd reccomend.
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Unfortunately the Chinese that made my Cayin dont provide this service... ;)
 
The Herbie's Audio Labs dampers arrived today, tried first only on the small tubes, as they are supposed to make more difference, sound seemed cleaner, particularly on loud passages, but a little soft... :rolleyes:

Then on the fat tubes, still cleaner, but louder, had to lower the volume a bit, not sure if it was more aggressive or louder... :rds2:

Let it run during dinner, come back and listen to my usual satelite at the same 50 loudness setting, too loud, had to lower the volume...

Got distracted on the internet, back to the sofa, defenetely more detail, wider stage... :D

Also ordered their CD-mat, started my reference 4 seasons, Stradivarius violin, without, then my "old" CD-mat, http://www.highfidelity-pur.de/Produkte/index.white-mirror no.1.html

The harpsicord on the background become very clear, and the violins more "liquid"...

Tried the Herbie's CD-mat, disaster, harpsicord blurred again, violins harsh and unpleasant, that one is flying back to USA...
 
tube_dampers.jpg
 
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I wonder if the heat dissipation/retention properties of these rings has more effect on the sound than their anti-microphony properties?

Probably more the case for those that use several bunched together on a single tube, a lá Unison Research.

Interesting nonetheless....

DT
 
The rings dont touch the tubes, they provide pressure and mass, only 3 small pads per damper touch them...

What looks like an interval on the white rings, is a pad...
 
melorib said:
The rings dont touch the tubes, they provide pressure and mass, only 3 small pads per damper touch them...

What looks like an interval on the white rings, is a pad...
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OK, but I meant generally speaking. I know this will be more of an issues with some designs over others...
 
Could be, not on this though, and they did make a difference, no wonder, with the subwoofer less than 50cms away... ;)
 
thrudge said:
I use these:

http://www.soundlabsgroup.com.au/pc/EAT-Cool-Damper/Valves/Sound

The improvement was immediately noticeable and I'm very happy with them D

I'm trying to remember what my amp sounded like before I got the EATs - off the top of my head, things got clearer and cleaner . I remember being a) surprised that the improvement was so significant, and b) grinning quite a lot. At £60 for four (from Absolute Sounds) this was a bargain upgrade. BTW, the EATs only fit smaller (ECC82-sized) valves.
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That's EXACTLY my experience tonight. 4 EATs for £60 - possibly the best £60 I have EVER spent on hi-fi.
 
I'm a herbie user too

They clean up sound on my phono tubes considerably and, less obviously, the line stage too with an impression of improved attack/dynamics
I couldn't get them to stay in position on my KR balloon 300bs (for the duration they stayed roughly in place they didn't appear to have any effect-possibly not a suprise given the tank like build!)
not hugely expensive either
h
 
Had some on my Eklipse valves and i thought they worked - but not easy to evaluate. Changing valves to NOS Mullards - bingo - BIG difference.
 
RobHolt said:
For small signal tubes just use wide heatshrink. Works and costs next to nothing.

Look like this in my phono stage:

IMGP0821.jpg
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rob, what preamp is this? is it just a phono stage or is it a full preamp. i am actually curious about sowther trafos on the left - is it a MC step-up or a volume control?
 

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