Tube dampers

I made a pair of the tube dampers featured in HFW last month which are based on pipe clips. Although they have stayed in position I wasnt too happy with them; they look ugly and dont get a good clamp on the tube. So I decided to have a go myself and I must give alot of the credit to Anex who replied to one of my posts regarding dampers.

Anex has used gas ptfe tape for his so a little dig around on the net told me that hi-density ptfe tape (as it is known) can operate upto 180 degrees. So a trip to see my local plumbers merchant led to the purchase of 4 rolls of the stuff at £1.25 each. The tape is just like the standard ptfe but alot thicker and alot easier to work with.

To form the base for the dampers the only thing I could lay my hands on was some 2.5mm copper wire I hade stripped from some cable. This was wound round some tubing a few times to give me a slightly larger diameter than the tubes. Next I simply built up a few layers of ptfe tape checking how they fitted on the tube. Finally once I was satisfied I had a tight fit and coated any lose ends I had with clear nail varnish (I used clear coz id already got it out for saturday night , any colour will do).

I made one for each tube, power and input and I can confidently say they make a difference, theres certainly more detail and the notes seem sharper if you get my meaning. The rings are tight on and havent moved a fraction with about 18 hours of use and I cant see there being any probs with the ptfe.

Give it a go.

 

Always wondered what they were for, I thought they improved the tube life? When my babies arrive I might have a go although I guess I will spend at least a month listening before I start playing.

 

ohhhh more tweaky crap i can play with now it's a possibility my amps will use light bulbs
cheers


julian

 

I spent about two days getting those right, there was tape everywhere. The MK1s used cork. That was ok up until the point it caught fire.

rsand: Possibly improve tube life very slightly but you may be thinking of pearl coolers which are heatsinks you put around the tubes. A good idea but the implementation isn't mean to be so great, the o-rings that hold them in place fail apparantly.

 

So what is the theory behind tube dampers?

 

Beats me. Stopping the envelope vibrating seems to help the sound.

 

Valves or 'choobs' as they are known stateside! Are adversely affected by microphony caused through vibration in their use or environment. You'll find that the manufacturers of musical instrument amps ie for guitars etc, seek out the low microphony valves for their cabinets as it cuts down on distortion brought about at the high sound pressure levels these devices operate within.

Damping is a good idea, if carried out safely, I would guess that a blanket covering to damp them down might encourage early failure due to retaining too much heat. The tube rings i have seen used look like a reasonable compromise, though plainly the best effect will be achieved by damping down the actual structure of the valve, which can be accomplished in another way entirely.

 

high temperature rubber 'O' rings have been used to good effect.

an easy solution to implement.

 

Like isolation platforms/sorbathane?

 

I think he means the structure within the tube itself, as I understand it, its the vibrations that can have an effect on the performance of the tube, similat to how vibration can effect a cartridge I suppose. Mine have made a difference, I just had to wrap another piece of ptfe round one of the rings last night to get it really tight.

 

Yes isolation platform/feet/cones/spikes et al can be handy,

I was suggesting DCT Cryo processing the valve itself, make that your starting point and all the other methods make still more sense. Cryo acts on both the internal metal and external glass bulb and reduces microphony within . Sound quality is noticeably better as a result. You'll find Svetlana are introducing this from a manufacturers point of view, and with some success. certainly I've noted that David Price, Ed at HFW has heard the results from them and been pleased. I am aware of a great many private customers and 'big names' in audio who are similarly pleased with valves I have processed. As is always the case this kind of statement starts a hoo haa, but the sound quality stands up for itself. There a members of the forum who have heard the difference and been chuffed.

 

I'd love to 'freeze' a set of tubes but those svets are pretty dam expensive!

 

t-bone, any pictures of you dampers? I might have a go, although not got my tubes yet

 

No worries I'll sort some out, I got a couple of new input tubes yesterday so I'll make another couple over the next few days.

 

Hi T-Bone,

I couldn't make out from your post if you mean that you are concerned your valves may be damaged by DCT processing, or just that the Svet Cryo is an expensive purchase. The latter I don't know about having never bought one, the former I can reasure you is not a worry. Correctly and carefully Cryo treating valves is, thus far 100% succesful over a volume beyond 1000 items. As I say, 'carefully and correctly' is the important phrase, anything else will not do.

 

Making my own tube damper is just not an option with the other DIY projects I'm working on taking most of my spare time. So I went ebay shopping and found what look like they should be great tube dampers and seem to be a great price.

http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&item=5767134216
and
http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&category=64629&item=5767133209&rd=1

They come as a set of 8 dampers per sale. and seem to be available in three sizes.

After the arrive down under sometime next week I shall let you guys know how the workout.

Alan

 

great value.

works out at 8 for about a tenner including postage.

nearly bought some myself!

let us know what you think when they come?

 

Yeah they look good, wonder what they're using. Some type of high temperature washer perhaps

 

looks like high temp silicone O rings, RS sell them.

 

I made some dampers for the Audio Research at the weekend using 1/16" copper tubing and Teflon that I, erm, borrowed from work and I have to say it was definately worth the effort. The sound is substantially better in every area. I an hearing new details and subtlety in every track that I play on the system. So for all you tube users, get some dampers immediately, its a no brainer.