tube dampener

[dancindave]

Got a nos mullard wit a tube dampener which amounts to a small rubber ring. Do I place it dead center on the tube, or is ther some obvious place I should put it?thank you.

[zaphod_phil]

Fit it around the spot where the upper mica spacer, supporting the electrode assembly, touches the glass.

[dancindave]

Thanks again!!!!!

[novemberrain]

NO way would I use "tube dampers" on real British Mullards. For starters "tube dampers" are mostly a gimmick, they don't do much. What they will do is create a luvverly mirror image of your Mullard logo when you roll 'em over it, the logo will wipe right off. Image is everything these days, a Mullard that says Mullard is wonderful, a Mullard that no longer says Mullard is a shame.

While I'm on the subject the best thing about Russian "Mullards" is that you can't take the logo off with steel wool.

[zaphod_phil]

Well it depends, on whether the tube is microphonic or not. If it's not microphonic, then no need to use the damper.

[LoWatt]

Use a half inch length of heat shrink tubing of the appropriate diameter centered on the tube. Works wonders on microphonic tubes.

[bigsbybender]

Like the Mesa SPAX7.........I just thought they covered the innards so they could sell a bargain basement 12ax7 for more money. I suppose it would quell the microphonics....in their insane high gain preamps.


j.

[novemberrain]

Well it depends, on whether the tube is microphonic or not. If it's not microphonic, then no need to use the damper.

For the record here's where I stand on microphonic tubes: For most practical purposes a microphonic tube is junk, replace it with a good one. I'll qualify that, I have hundreds of 12AX7s and I get more every week. I don't need hundreds but there was a time when I didn't have enough so I devised a mechanism to keep the 12AX7s comin' my way, nuff said.

Like any other rule there are exceptions. Every so often I'll run into a tube with exceptional gain and exceptional emissions, unless they sound like the Devil is tryin' to talk to me I'll try to make those work. Think about it for a moment, ANY preamp tube is goin' to make a certain amount of noise, a premium tube is going to be hot and juicy WITHOUT the noise. Those were the ones that were graded as 7025s and ECC83s, they're supposed to be premium 12AX7s.

I keep a very small assortment of microphonic tubes for interesting effects and I have them sorted according to what they do. Some are about burnt but they'll instantly give a low fidelity tone to a track that requires a low fidelity tone. If it don't work in the mix it don't work...

[zaphod_phil]

Unfortunately, most EF86s are intrinsicly microphonic, due to how they're built and their very high gain levels. And can't just say they're all junk.

[novemberrain]

Unfortunately, most EF86s are intrinsicly microphonic, due to how they're built and their very high gain levels. And can't just say they're all junk.

I run into the same thing with 6SC7s although they're quite different from EF86s. SC7s were supplanted by 6SL7s so most of the 6SC7s I see are from the mid-'50s at the latest and many of those are microphonic. I diligently sort through through 'em to find the best ones because even though I can use 6SL7s or 5751s in the same circuit 6SC7s have their own thing goin' on.

I still think "tube dampeners" or whatever them busted condom hula hoop thingies are called are mostly a cop out in many applications. SURE you paid way too much for that Telefunken or that Mullard and sure, the guy that sold it to you is laughin' his ass off 'cuz HE culled it from his stash 'cuz it was microphonic. I don't care if you stick ten "O" rings on it, it's STILL going to be microphonic.

[dancindave]

what i was hearing was a slight rattle at the highest volumes, small,like a bb,when i put the dampener on, it went away.

[rectifier]

what i was hearing was a slight rattle at the highest volumes, small,like a bb,when i put the dampener on, it went away.

I've experienced the same thing and I believe they do make a difference (especially in a combo amp where the tubes are subjected to a lot of vibration).

[tcjeffects]

Yes, they do work, and work well indeed. What's a bigger hype is NOS tubes. Just like new ones, you roll the dice when you buy on whether it's good or not. I've spent plenty on "holy grail" mullards, telefunkens, etc. to find out some sound like crap, some incredible, and all the others somewhere in between. Thing is, the same thing occurs with $3 chinese and russian tubes. And these days, you can buy a raft of $3 tubes for the cost of setting up your amp with "NOS".

I recently tried tube dampeners on an el84 equipped amp. I found it to make a difference more, with the poorest quality tubes....or should I say the tubes with issues. Some of them weren't cheap, but they had issues.

[tubetwang]

there's tube dampeners and there's tube dampeners...

50 cent's car parts red dampeners are for proletarians.
http://herbiesaudiolab.home.att.net/index.htm titanium dampeners are for Cocaine Cowboys.

They were all the rage 5 years ago in tube hi-fi d.i.y forums.
Trickle down caper.

I've tried them in my hi-fi-search-for-optimum=sound=reproduction-days, and i'll let you experiment on your search for holy grail sound.

There's only one way to know for shure.
A-B it in your set-up.
Don't start with the Titanium but...

[zaphod_phil]

I've spent plenty on "holy grail" mullards, telefunkens, etc. to find out some sound like crap, some incredible, and all the others somewhere in between. Thing is, the same thing occurs with $3 chinese and russian tubes.

But the NOS tubes that sound incredible, sound *really* incredible. And unless you've been sold tubes out of someone's junk pile, quite a lot of them should sound great to incredible. IMO with the non-NOS they will mainly go from bad to great, but few if any "incredible". So I mainly use NOS or good quality pulls, and I don't pay silly prices for them either.

Like I said before some kinds of tubes tend to need the the dampener treatment more, even if they're perfectly fine tubes in terms of their electrical and sonic performance. I am using some 12BZ7s these days, which are taller than 12AX7s and have a very long electrode structure. They sound fantastic, but often they can be microphonic. So dampeners seem to really help with them.

[unchained]

Hey Zaphod, have you used 12BZ7's in an 18watt circuit? If so, how do they compare to 12AX7's?

[theundeadelvis]

My (JJ) rectifier would rattle real bad when I played a certain chord. I kept thinking "whose ringing that bell?" Anyway, I went a got a big O-ring from the hardware store and put it on the tube, and voila, no more bell ringing.

[LeeMo]

3/4" silicone ring , part # ors-018
http://www.smallparts.com/products/descriptions/ors.cfm
Also available locally at Autozone as a fuel injector ring.

LeeMo

[zaphod_phil]

Hey Zaphod, have you used 12BZ7's in an 18watt circuit? If so, how do they compare to 12AX7's?

No, I haven't in an 18W. I think they would work well in a TMB or possibly in a PI, although you would need a bigger cathode resistor value to bias a 12BZ7 correctly.