Tube damping rings: Do they make a difference?

I'm wondering about the use of tube damping rings and their use in vintage tube gear. What do you think of them? Do you use them? How do they affect the sound? What kind/brand do you recommend? Steve, do you use these things in your vintage amps?

 

Check out these: http://herbiesaudiolab.home.att.net/

My equipment (almost all tubed) sits very close to my speakers, so these little things make a noticeable difference. Hey, with a 90-day return policy you can't really go wrong in trying them!

John K.

 

Herbie posts here.

His Halo's are fantastic - the perfect solution, with no downside. They are cheap enough for most valve owners - someone with a pair of Hurricanes or a couple of big Atma-Spheres may start adding up the cost and balk. Normal people will think of them as good value.

I have many different sized Halos - they are on the TJ globes, the GZ37s and the 6SL7s in my amps. I also have them on the eight 6H30 "super-tubes" in my pre-amp; and I have some of the small ones on the XLR connectors. Whatever.

Get your measuring stick out and figure out exactly which ones you need. Tubes cost a lot of money, but will last longer if you look after them - hence the Halos. I didn't have any microphonic tubes when I bought the dampers though.

Give Herbie (not really his name, but he's fine with it) a bell - you can't go wrong.

Regards,
Geoff

 

Geoff,
I found this blurb on the net. What do you think of what these people are saying?:


All vacuum tubes exhibit microphony to some extent, the generation of spurious sounds in response to mainly airborne vibration. This is usually low in level but mixes with the music signal to add subtle, pervasive “grundge”, muddiness and harshness. These effects worsen as the sound pressure level increases. Of course, all electronic components have this general problem to some extent, where platforms, special feet, damping and weighing down the chassis are the curative measures. With tube microphonics, the active devices themselves, the vacuum tubes, need to be separately damped.

Many audiophile accessory tube damping products are being marketed, but most are a kind of negative tradeoff where there is some improvement in apparent clarity, but longer term listening reveals that there is also an unacceptable loss of life and transparency of the overall sound.

Other negative effects of various commercial tube damping devices can include a metallic “ringing” quality and loss of dynamics. The most likely theoretical explanation is that the high frequency resonances of the tubes glass envelope are indeed being damped and other vibrations are being reduced, but the fields surrounding the tube's plate, grid and cathode are also being affected. Introduction of material with poor dielectric properties or metals with remnant magnetic fields and inherent eddy current effects are indirectly affecting the electron flow and therefore the music signal.

We have found only two devices that have almost entirely positive sonic effects in reducing tube microphonics. These are special types of “o”-ring (FEP Teflon-coated silicone) which can be obtained in the right size to fit onto miniature (12 AX-type) tubes, and plain silicone o-rings which much improve other types such as 2A3, 300B and 6SNT. Though certainly not designed for this purpose, these o-rings make amazingly effective damping devices.

Next best, but introducing noticeable muddiness and loss of midrange information, are the 3M elastomeric damping rings.

Sources: FEP Teflon coated silicone o-rings, size 116, fits miniature (12AX7-size) tubes, silicone o-rings, size 133, fits 2A3 an 300B types: McMaster-Carr (562) 692-5911, catalog numbers 9319K26 (#116), 9396K154 (#133); 3M Tube damping rings: Michael Percy, 530-470-8650

 

You may have heard of this guy:

Steve Hoffman, Music Restoration Specialist
http://www.stevehoffman.tv/

"INSTANT MO' BETTER!!! My VAC 300B amp sounds instantly less wobbly, less microphonic, tighter bass, better everything."

Look at some of the names praising the Halos here:

http://herbiesaudiolab.home.att.net/reviews.htm

Herbie's tube dampers, as opposed to "plain silicone o-rings", are designed to damp tubes and not obstruct cooling or generate localized hot spots. I'm sure you'd be happy with them. If you wait a bit, Herbie might chime in.

Regards,
Geoff

 

I'm sold.

 

Really?? Okay, this is interesting. Steve, why not? Also, I was wondering about those little metal tube covers on vintage amps. Should those be removed to keep the tubes cooler or anything? Am I to understand that you are saying not to use tube dampers for vintage gear in general or are you just speaking about these Halos in particular?

 

That makes sense. So, do you think proper ventilation means removing those little metal can covers on the preamp tubes? I'm wondering about that.

 

Those metal cans provide shielding. You may let in all sorts of nasty electronic noise and hum by leaving them off. Leave them on.

As for ventilation, that vintage gear was built well, usually, and you'd be surprised how hot they can get, but still they run for years and years reliably. I am thinking of an old pioneer integrated amp I used to have, and oh boy did it's PP EL84's get hot ! Still, it was still running well 20 to 30 years later...

 

I can only speak from from my own experiences.

In my previous amp, the most important tube was the 6SN7 in terms of sonic impact. After rolling through nearly 7 NOS variety's, I realized that even top-rated tubes that have been cryogenically treated can still be VERY microphonic.

The Herbie-dampers DO work very well: they lowerd the noise floor considerably, which I can only attribute to to the removal of microphonics. The microphonic vibrations did not add, but rather took away from a beautiful sounding 1942 Sylvania NOS 6SN7 for example.

I think the heat issue and microphonics are two seperate things. If a tube is microphonic, no matter how well it is ventilated, it will still be microphonic, which is less than ideal. Tube microphonic noise and vibrations should not be considered part of the "character" of vintage piece of hifi equipment. I doubt they were built into the original product design.

 

I just got a set of HAL-Os for my (modern) monoblocks and I was really pleased with the effect. Like others noticed, the noise floor lowered so there was more nuance, and the tonality improved. They also didn't damp the life out of the music.

I didn't think my tubes exhibited any obvious signs of microphony before, so I was surprised by the difference. It's like the song says, "You don't know what you've got till it's gone."

With the 90 day trial period, there really is nothing to lose. And if you don't have to open your casework to put them on, application is a breeze.

 

I use silicone tube dampers

I use the silicone tube dampers that Galen Carol sells. I put two of them on each of the signal tubes of my McIntosh MC-30s and Dynaco ST-70, and I believe that they brought focus to the upper frequencies.

But hey, they're really cheap, so you don't have much to lose.

 

Any opinions on why one of these types of dampers would be better than the other?

 

I've tried 3M(?) rings in the past. They were tight going on and I think the tube heat sort of sealed them to the tubes. You could still take them off, but they turned hard and stiff.
The Galen Carol rings (which I haven't used) are described as high temp. I may be mistaken but they seem to only have the one size for smaller tubes.
The HAL-Os have high temp dampers and are really easy to put on because they're "C" shaped and come in sizes that fit large tubes too.
You could try the Galen Carol for smaller tubes and the HAL-Os for the larger ones.

 

For 12AU7, 12AX7, 12AT7 TUBES

I found some O rings at PEP Boys. For Engines. So High Temps are OK.

"O-Tite!" brand

Width 1/8"
I.D 11/16"
O.D. 15/16"
QTY 5/pkg.
UPC 037495642095
Colo(u)r Black
Price $2.50/pkg.

They roll on or off easily. They don't get gooey or hard. And best of all they reduce microphony quite nicely.

I settled on 3 per tube for the 12AU7s in the Foreplay Pre-amp. One at the top mica, one at the bottom mica and one between those.

I don't have a picture, but this is what it looks like.

o

(not actual size)

Seriously, low cost, high return. IMO

FM

 

At that price it will be worth it just to experimwnt a bit.

 

I have had tremedous improvements from Audio Research tube dampers on my ARC VT100.

They are less expensive than Halos and work as well.

 

Just wondering, LeeS, have you tried HAL-Os?