Tube dampers for my KR300BXLS

[Deang]

These were actually hard to find.

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

[lynnm]

You might also want to look into Pearl dampers. They are made by Peterson ElectroAcoustic Reasearch Laboratories - I love a really clever acronym. They work well and are cooler than dry ice !

http://www.diyhifisupply.com/tubecool.pdf

[NOSValves]

Lynnm

So where can you buy them ?

[mobile homeless]

Before the World runs out and buys tube dampers of various designs, I would not do this unless REALLY plagued with problems. IT has been my experience that tube dampers tend to take some of the life from the presentation. I just have never liked them in any of my amps (or preamps for that matter). So if you have a severe problem, yes. But, by and large, I dont think tube dampers should be used if they can be avoided.

kh

[mike stehr]

What about the interconnect dampers?

[lynnm]

The Pearls can be had from Classic Audio or probably directly from Pearl, (their address is at the top of the article that I linked you to). I don't use them as I don't have any discernable problem with microphonics or excessive heat. I do not wish to imply that I believe that dampers should be routinely applied to tubes. Before I bought Pearls or any other dampers I would attempt to correct any problem before resorting to any add-on solution. From where I stand the most logical cure for microphonics would be to swap out any microphonic tubes in your amp. The drivers would be the most likely culprit.

If that did not solve the problem then dampers might be indicated.

That said the Pearls really do look interesting in a vaguely industrial sort of way.

[Deang]

Mike, interconnect dampers really seem silly to me. I saw that and started laughing. Talk about taking an idea to ridiculous limits.

Kelly, I don't know about that. Last night I got off work and had come up with an idea for some make-shift ampstands. I had some 26" Wood Tech stands that I used to use for my RB5's, and removed the bottom plates from them. The base-plates were still spiked. The bases are fairly large, and measuring things out showed I would get 80% coverage under each amp. I then removed the feet off the amps, and inverted them, placing them on top of each base. I used very small rubber sticky's under each spike, and then sat the bases on top of my table insert -- and then placed the amps on top of the inverted feet. This nifty little set up removed ALL mechanical vibration. I sat a small, half-filled glass of water on the edge of one the amp and let it rip. I simply watched the movement of the water in the glass to assess the amount of vibration I was getting.

Experimenting with the music showed NO decrease in the amount of ringing I was getting from the output tubes. It is very simple to do. I just raise the volume level, and then mute the music in mid-stream -- iinnnggggggg. Nice. I spent a very long time last night thinking about this phenomenon. Acoustical vibration is an interesting problem. What is really going on here? I believe the tube internals act much like a tuning fork, responding to their own resonant frequencies found in the sound, and the glass is acting as the transmission medium.

As far as I'm concerned, it's pure distortion. It's not part of the signal, nor is it part of the source material.

Your view seems to be saying that a little bit microphonic distortion adds to the output in such a way as to improve the sound. What else could you be saying? O.K. Master Yoda, I'm going to have to chew on that one for a while.

I would think that ANY movement of the filiment(s), adulterates the signal, and decreases tube life.

Hmmm.

[mobile homeless]

Sounds like you have some bad tubes. Or something amuck. Regardless, getting that amp stand to top notch performance will HELP your whole system.

As for tube dampers, try them out. I have found they actually tend to kill some of the air and life to the presentation. Your results may vary. Obviously, as I said, if you have serious problems with microphonics, you might need them. I jsut prefer to be without. Same reason I dont like SOFT SHOES and NAVCOM etc under my tube amps/equipment anymore....or a thick rubber mat under my records.

You also could have a problem with that circuit too. Something sounds amuck. That much ringing is not reported that often. Cary amps used that tube for several years and I havent heard much report of ringing. I even think RAndy Bey has a pair in his Laurels. Something is up.

kh

[Triode Pete]

I recently swapped amps in my K-horn system from 2A3 SETs to 300B SETs, which use a pair of RCA 5692 driver tubes and KR 300BXLS output tubes.

At high volume levels, I noticed some tube ringing when "pausing" a playing SACD. Appears to be the KR 300BXLS. I tapped on the thick glass ST-16 envelope and microphonic ringing can be heard through the midrange horn.

I have not experienced this phenomenon when using my vintage black-plate 2A3 Sylvania's.

There may be an inherent microphonic problem with the KR 300BXLS??? I am very surprised though...ART Audio exclusively uses the KR tubes in their very expensive tube amps...and the KR tubes appear to be very well built (they're heavy) and designed to last a long time.

A post on the Audio Asylum (Tubes Asylum or SET Asylum) about the KR 300BXLS microphonic ringing may be worthwhile.

Audios,

Pete

[Deang]

No circuit problems. The ringing is associated with both output tubes.

A search on the Welborne Forum will show that I am not alone with this problem and this tube.

Several things to consider here that make my situation somewhat unique.

1) My listening room: Though the room is very large (long), the speakers and equipment are situated at the end of the room which is almost like a "shell". See the attachment in case you don't remember. Acoustically speaking, it's dynamite, and the air in this small area becomes excited very easily. This property is now working against me.

2) Placement: The amps are close to the floor. Though I have mechanically isolated the system, they are in the worst possible location for controlling acoustical vibration. If you haven't done this in a while -- crank those Cornwalls up to about 96db and put your head between the speakers and close to the floor. The majority of turbulance is down there. What I need is a good vertical rack, which will move the amps further away from the speakers, and elevate them where things aren't quite so active.

3) The tube: If you go to the KR site, you can compare the KR300BXLS to the KR2A3. The KR300BXLS is HUGE. In the pictures, it almost appears that the difference in the size of the envelopes is the same as the difference between a KT88 and EL34. There is a hell of a lot more glass here.

4) The music: There is more in my music than there is in a Jazz Quartet. I just think these tubes are prone to ringing, and most just don't notice it because of the type music they listen too. Also consider that most who used this tube, use it on less than efficient speakers. Uhh, 18 wpc on some 89db/w speakers isn't likely to produce enough SPL to excite any tube.

The tubes are fine, they sound great. Anything below 92db and there is no discernable ringing at all. I've ordered the dampers. It will be interesting to see what I gain and what I lose. Besides, it'll fun goofing around with them.

[jazman]

dean,

Maybe it's time to write the manufacturer for "no cost" replacements. SPL should have nothing to do with the ringing in the tubes unless the tubes are faulty.

Klipsch out.

[Deang]

So, the thunder claps and the windows don't rattle?

The output from speakers can vibrate floors, walls, turntables, CD players, and yet -- you would have everyone believe that sound pressure waves smacking against a glass envelope -- shaking cathodes, thin wires, etc, -- are unaffected.

ALL tubes "ring" to one degree or another.

[jazman]

dean,

Do whatever, and believe whatever, you want. It's certainly not my problem. The bullhit is in your head if you're not willing to consider the "possibility" the tubes may need to be replaced. Tubes were used in applications with more environmental noise than audio systems. Enjoy!

Klipsch out.

[Clipped and Shorn]

Where can I get good Audiophile Dampers. I have been simply using rags as gags and the occasional restraining order, but would like something more elegant and, of course, more expensive and preferrably something which cannot be proven one way or another to actually do anything except in my imagination.

-c7s

[mike stehr]

Clipped,

I think that guy in your Avatar has that Audiophile Damper your looking for,

just get a Mothra power cord and plug 'er in!

Would ringing have a effect on Pentode tubes?

I recieved a Complimentary CD in the mail from a Portland Label.

Dark ambient stuff, obnoxious bass levels.

With one sub next to the CD player, one track made the CD player skip rather hard, literally stopping it and retrack.

Vibrations everywhere, curtain rods, glass, paneling, the metal enclosures on the little Eico amps were buzzing.

This was on the trail listen of this CD.

But I didn't here any tube ringing. Or I don't know what the hell to listen for, or the junk I use isn't resolute enough, who knows.

I haven't experienced any tube ringing with all the vintage garbage I have, but I don't know what to listen for either.

And I just use old name brand tubes, sometimes NOS, most the time used.

[NOSValves]

Mike ,

^{"I think that guy in your Avatar has that Audiophile Damper your looking for,}

just get a Mothra power cord and plug 'er in!

To Funny !!!!!

[Deang]

I believe what I believe because I did 9 hours of research on tube manufacturing techniques and associated problems. Keep in mind that most tubes used for audio, weren't even initially designed for audio applications. These tubes were used in circuits where microphonics would not have been an issue. NOS in particular, were NEVER checked for microphonics, as it was just not a concern at the time. Microphonics and associated "ringing", are actually completely normal, and some microphonics is actually what contributes to a tube's sonic "character". Excessive ringing simply means the tube is more sensitive to mechanical and acoustical vibration -- and additional measures have to be taken to get it under control -- it does not mean the tubes are "bad".

The possibility that the tubes had a problem was the first thing I considered, but after reading a multitude of other posts from people experiencing a similiar problem, and of course, listening to the system -- I ruled it out.

At any rate, your off the cuff comment that loudness levels should have no effect on the tubes -- was incorrect. You also failed to address my reasoning on why I thought so.

I didn't understand why you came off with that original post like it was the definitive, final word on the subject. The "Klipsch Out" signature also annoyed the piss out of me.

From the Audible Illusions site, regarding the use of NOS in their preamps.

"Also, be cautious in purchasing NOS tubes. While some of these tubes have excellent sonics, they also have very high microphonics/ringing and distortion. They are unreliable when used in most modern preamplifiers, particularly in no-feedback line stage designs like the Modulus."

From the KCA site, primarily dealing with guitar amps.

Q: My tubes are microphonic, what do I do now?

A: In reality, every tube is microphonic to some degree. The question is, is the tube usable in your application?

Tapping on hot tubes while in operation can indicate how microphonic a tube is, but it's not a good idea to do this. You can damage a hot tube by tapping on it, so tap GENTLY if you insist on doing this.

You will likely hear thumping through your speakers when you tap on tubes. Some thumping is definitely normal in average tubes. Ringing can sometimes be heard. This is not necessarily a bad thing either. Note that the first gain stage (or high gain stages) in most amps will be more susceptible to microphonics than later stages. If a tube acts badly in the first or high gain stage, try it in a later stage. Phase inverters, for instance, rarely have problems with tubes that have higher than average microphonics.

VERY microphonic tube can be unusable. They will cause your amp to feedback with no signal input, much like a microphone feeds back when held in front of a speaker. Other unusable tubes will create notes of their own while you play your guitar. These tubes are obviously too microphonic and must be replaced.

Q: So then, can microphonics be a good thing??

A: Yes. Many players and audiophiles feel that microphonics add to the tone of the tube. I agree with this. Comparing totally "dead" tubes, ones that make no discernable sound when tapped, to more "lively" tubes, most people prefer the tone of the more lively tube.

From the Soundstage Review on the Art Audio Diavolo Amplifier. http://www.soundstage.com/revequip/ian04.htm

While I was able to forgive the VV32B's mildly aggressive treble due to otherwise stupendous sound, I have a problem of a different nature to report. This tube rings like crazy, even at moderate volume levels. While I certainly enjoyed my time spent with the amplifier, I was really annoyed by the ringing of the output tubes. At first, I wondered if I was driving the amplifier too hard, but when I listened to music at really quiet levels, I could still hear the ringing. I placed a call to Joe Fratus (Art Audio USA) and detailed my problem with the tube. KR manufactures three different versions of the VV32B tube (cylinder blue glass tube, blue glass tube, glass tube that looks like a 300B), and my review sample of the Diavolo came with the cylinder blue glass tube. Joe sent me a replacement set of 300B-style 32Bs, and I sent the other set of tubes packing. The new tubes were dramatically quieter, but I did still hear some ringing at loud volume levels. I suspected that if I better isolated the amplifier, I might alleviate some of the ringing. BINGO! I placed three Black Diamond Racing Cones underneath the amp and also stacked three #4 Vibrapods under each of the tubes on the underside of the chassis. The ringing didn't completely vanish, but the difference was quite audible. Another contributing factor to the ringing has to be the fact that the tubes are naked. Art Audio does offer a specially made tube cover for an additional $300, but I consider this unacceptable. The KR tubes are not inexpensive (not to mention the amplifiers cost), and I can't help but wonder if this great amplifier would sound almost unbeatable if the tubes were quieter. Happily, Art Audio has just begun supplying the Diavolo with a new iteration of the VV32B tube that they claim alleviates the problem with ringing.

Another comment regarding "ringing" and the Mullard CV2493. http://www.soundstage.com/tubeor/tube2.htm

Yes, and again, the Mullard 6922 is a great example of this situation. The later model of this tube, called a CV2493, is a great tube. It sounds relaxed and extended, everybody loves them, nobody hates them except for one thing. This tube is unusually sensitive to vibration, so you can't use it in certain preamps such as an Audibile Illusions Modulus 3A, which feature a tremendous amount of gain. If your amplifier has a lot of gain and if your speakers are really efficient, Mullard CV2493's will start ringing. So that's why I don't like to say that there is any absolute, unqualified "best" tube it depends on the individual component and everything else downstream. Some products are more sensitive to either noise or microphonics than others, so any N.O.S. tube decision must account for these factors. Ultimately, it's a matter of synergy.

From an article at Enjoy the Music. http://www.enjoythemusic.com/magazine/viewpoint/0902/karlskorner.html

Now I want to mention a variety of facts that may provide more insight into the background and some problems with these audio tubes. The giant R.C.A. receiving tube division was auctioned off in 1976, a victim of the overwhelming popularity of transistors. This effectively killed the supporting industries. All those tiny parts inside the tubes that had become perfected over the decades were about to become history. If ten years later, someone wanted to resurrect quality vacuum tubes it would be starting over on a lost art that wound up with little demand. The demand from audiophiles and music lovers is a grain of sand lost on a wide beach. Some tried to resurrect them in the eighties with identical appearance but unfortunately inferior performance, either brightly harsh or some being darkly veiled sounding. The main key here, is when was any individual tube made and where? Markings on the boxes are often meaningless. Markings on the tube tend to be more meaningful - sometimes. If a tube says "Germany" that is unfortunately, legally not the same as saying "Made in Germany". That's a probable scenario for the flood of Phillips branded JAN marked tubes still floating around. Look out for what some rather infamous tubes connoisseurs refer to as "Telejunkens". Evidently some original Telefunken machinery fell into Russian controlled East Germany hands so that the tubes appeared to be the real thing. They eventually flooded the market with them and are relatively common to this day. Seemingly most, if not all, were marked as 6922 or E88CC types and made in Germany, which they were. Audio quality is definitely inferior - beware. As a result companies such as Siemens stamped their tubes West Germany.

As for the frame grid tubes I've briefly discussed, Andy Bouwman mentioned to me that some time ago he purchased a forgotten stash of Siemens & Halske 6922 and 7308 tubes. These are often regarded as the best, even surpassing the general reputation of Telefunkens. He said that he had gotten 600 of them and only approximately 450 were good enough for his standards for audio use and sale. About one fourth were audio rejects. Wow I said, "I thought that the SH logo Siemens were the best tubes and had the best quality control." "They were", he replied, "but remember these were not designed for audio use and so there was little need for quality control for microphonics and the unbelievably thin wires in the frame grid are extremely sensitive to microphonics!" Even fairly loud music shakes hundred pound loudspeakers and fifty pound turntables or CD players. Think how it can affect the thin glass of those tubes. It causes ringing, exaggerated treble notes and general smearing. It is easy to grossly test for microphonics, but if you've never done it, I'm not about to tell anyone to open the case of tubed equipment with its dangerous high voltages to check for microphonics. Someone else will have to tell you what to do. Be careful if you decide to try these tubes in your preamp as in some equipment designs each of the tubes (usually two) in each left and right section must be carefully matched or very serious problems can result.

The above comments pretty much hold true for the other famous series of mini tubes, the 12 series i.e., 12AX7 and its many variations plus 12AT7 and 12AU7. Here must be added genuine RCA manufactured tubes and a few others. Also with these tubes, genuine Telefunkens were more common than they were with the discussed frame grid types. The same order of fullness/richness tends to prevail with these as with the frame grid types. Place the RCA's just before the more neutrally balanced and not quite as soft sounding Telefunkens. The famed neutrality of the Telefunkens is more readily apparent and perhaps important, when used at the input of many tubed amplifier designs where feedback loops exaggerate minute differences between tubes. All brands were affected by the aforementioned industry decline and lack of the highest quality parts and needed special chemicals for manufacture. Varying by company, by the early to mid seventies the highest quality mini tubes had become a part of audio history. Some resurrections were attempted.

Original Tube Dampers

These beautifully finished brass damping rings weigh a quarter of a pound. Yet they are available in the correct size for nearly all of the mini-tubes mentioned in the above tube article. They are available from Andy Bouwman at Vintage Tube Services. Seemingly a simple design, but they are not quite as simple as they appear at first glance. Bouwman particularly recommends their use with zero feedback equipment and SET amplifiers. There are many logical reasons why these heavy rings, looking like a man's oversized wedding band, can benefit sound quality. With "cageless" tube gear they add an attractive masculine touch to exposed tubes. I had 3 microphonic tubes, 1 was microphonic in the extreme, a hard glance at it would almost cause microphonic noises. Putting these dampers on all 3 resulted in 2 cures. Burial is the only alternative for the third one. Relatively expensive ($64) but worth their price in many situations. Andy does like to communicate by phone also - (616) 454-3467.

From the FAQ link for Halo Tube Dampers. http://herbiesaudiolab.home.att.net/faq.htm

Q. Having "some/little" microphonics in the tubes is important (most tube audiophiles know this)--- it's one of the things that make tubes sound the way they do (over solid state). By eliminating the microphonics, the tubes' sound would be totally changed (perhaps lose that warm, open/layered, and transparent quality). What are your thoughts/comments on this?

A. Unwanted microphonics, caused from transformer hum and other factors, add fuzziness to musical detail, blur the focus, add glare, and cause other distortions. The HAL-O eliminates these problems, but in areas where the tube is not suffering from any of these problems, the HAL-O Damping Instrument does nothing at all.

Sometimes, a small loss of microphonic "air" is replaced with sharper attack and better-pronounced decay, more natural tones, better imaging, larger soundstage, truer music. You'll hear the real "air" inherent in quality recorded music.

As for warm/open-layered/transparent qualities, HAL-O users have found that the HAL-O enhances and improves the unique qualities of their tubes. For example, a "warm" sounding tube sounds better because the tonal qualities are more pure and true-to life. The "warmth" is still there, with a more focused soundstage. Open-layered and transparent qualities are enhanced because the background is quieter, imaging is more focused, decay has more of a purity of tone. Tubes that work well on the high end have less fuzz and glare, yet keep the same high-end frequency response.

HAL-O Damping Instruments have been tested at JJ Electronic Laboratories and found to have no adverse effect on the frequency response of vacuum tubes.

"Klipsch Out" Indeed.

[mobile homeless]

Well, at least I feel better... Three or four of my comments to you were verified by other listeners, reviewers, etc including solutions and problems with damping of tubes too much. I am feeling quite spritely now! Heh....

READ: I have something due and here I am wasting time here!

kh

[Deang]

I agree to a point -- I don't want to kill the tubes, just quite them down a little. The Halo's provide some damping to the glass, without "smothering" the tube like some other solutions I've looked at.

[edster00]

When I first mentioned tube dampers it was Hal-O I was referrnig to, a fellow I purchased some equipment from swears by them (I just couldn't remember the brand name).

FWIW, jazman ends every post with "Klipsch out."