Ringing in the tubes

[medward0]

My quest for quiet tubes for my ET3SE continues and I've ordered some 6922s from CJ and hopefully they will do the trick.

I've tried several 6922 brands and some EC88s too.

The 6922s start to hiss within a few weeks and the EC88s (like the National (Mitsu) & EAT) just ring and ring when I change the volume.

I put Dynamat Extreme all over the inside of the top cover (thanks Ronenash!) and it definitely improved the overall sound...lots quieter!

But even with the Dynamat in place and a relatively new 6922, changing the volume causes a lovely very high pitched ring that goes away after a few seconds. This ringing is not there with all tubes.

I know it is the Holiday season and all, so ringing is not entirely unexpected. :D But I actually found myself thinking, "well, you wouldn't have to mess with tubes if you had a JC2 you know."

I'm crossing my fingers that the CJ tube lots are quieter.

The good news is that the EAT EC88s sound spectacular in my ET205S!

[tdelahanty]

Your ringing might be caused by mechanical vibration when rotating the vomume control, try some tube dampers or shields.

[Rayooo]

I've had a couple cases where a particularly micro phonic tube would pick up mechanical noise from the relays during volume change. (I've seen this in ET3, ET5 and GAT)
the effect does sound somewhat like "Jingle Bells" :scratch2:

What was a little surprising to me, even with the tube isolation mounting in ET5 and GAT, the mechanical relay noise pickup seems just as pronounced.

I've also had tubes that did not ring with volume-control change, but remained somewhat micro-phonic. I've picked an arbitrary line where if the tube rings with volume control changes, I consider it defective.

The next test is a very light tap with finger. Some tubes that don't ring with volume-control adjustment, are still susceptible to light finger tap. Others are impervious to pretty much any micro-phonics including finger tapping.

A few months ago I exchanged a new set of NOS Mullard's for the ringing-with-volume-control effect.

As I found out, this specific tube supplier measures the tube performance in a tube tester, but does not make any attempt at listing to and/or measuring the tubes micro phonics.
The replacement set have been great now for what has to be 100 or more hours at this point. :yes: (Fingers crossed)

In each and every case, I've tried with and without the generic neoprene (or whatever they are made of) dampers, as well as some nylon spring type. In no case did the tube damper(s) make any significant difference in the ringing.

I'd suspect if I were measuring the level of micro-phonics using some more accurate means, tube dampers would at least have some effect.

GOOD LUCK! :D

[medward0]

Thanks, guys.

I've been using dampers on the tube in the ET3SE as well. I've even tried a cool damper from EAT and no difference in the ringing.

Glad to know that my unit is not all that unusual and that others have had similar experiences, but sheesh, what a pain. Good thing I love my gear....

Yea, I guessed that some of the tube suppliers just put the tube in a rig and do some simple testing. Some even say they check for microphonics...hmmm, not so certain they do *by listening* or the tubes are damaged in shipping.

What we put up with for that magical CJ sound. :music:

Here's to hoping that the tubes I've ordered from CJ will be silent.

[Smctigue]

EH 6922's sourced from Audio Research are VERY quiet and not at all microphonic. Perhaps CJ is sourcing EH as well?

[medward0]

Thanks, Smctigue. I didn't know that Audio Research also had 6922s. Great to have another source!

[ronenash]

Medwardo,

How are the new tubes working out for you?

[medward0]

@ronenash, still waiting for my tubes from CJ. I think a combination of the holidays and bad weather has delayed them. I will update when I get them in the pre.

In the meantime, I've got a pretty noisey tube, but hope carries me through until the new ones arrive.

[medward0]

New CJ 6922s in the house for the pre.

First one had crackling in the R channel and I'm considering sending it back.

Second one has no crackling and is currently in and well behaved.

Both have a very small bit of hiss if my ear is up to the tweeter, but not nearly as much as some of the other 6922s I've tried.

Happily, now that the holiday season is past, no more ringing tubes. :thumbsup:

[vintage_tube]

New CJ 6922s in the house for the pre.

First one had crackling in the R channel and I'm considering sending it back.

Second one has no crackling and is currently in and well behaved.

Both have a very small bit of hiss if my ear is up to the tweeter, but not nearly as much as some of the other 6922s I've tried.

Happily, now that the holiday season is past, no more ringing tubes. :thumbsup:

You may want to ask member Miles how his Gold Lion 6922's were in his CJ gear.:dunno:

Happy Holidays Folks,

Bob

[Smctigue]

New CJ 6922s in the house for the pre.

First one had crackling in the R channel and I'm considering sending it back.

Second one has no crackling and is currently in and well behaved.

Both have a very small bit of hiss if my ear is up to the tweeter, but not nearly as much as some of the other 6922s I've tried.

Happily, now that the holiday season is past, no more ringing tubes. :thumbsup:

Are they EH?

[medward0]

Yes, they are EH 6922s with a lot number of 11 09.

Got about 6 hours on the tube in the pre and so far, so good.

[USCG65Pilot]

Medwardo - due to a similiar problem I am curious what your outcome was? Regards

[medward0]

@USCG65Pilot - I've now had the same tube in the pre since I wrote last December. It was an EH 6922 from CJ. This is the longest that a tube has ever lasted in the ET3SE before becoming noisy.

I play the system at least a few hours a day and typically all weekend long...so 9 months is pretty good IMO.

The tube is hissing pretty loudly right now and I need to replace it, so I'm about to try my had at "tube roulette" again. But, I've ordered more from CJ last week and am confident that some of the 5 I've ordered will work.

It just seems the luck of the draw in getting a quiet tube, but I must say that the CJ sourced ones have been the quietest.

[sleepysurf]

I haven't had any crackling/hissing with the 6N30p tubes in my CT-5.

However, a few years ago I had that issue with my Modwright SWL 9.0, which was "cured" by CAREFUL application of Caig Deoxit and Pro Gold to the tube pins. I made sure I didn't get any liquid where the pins enter the tube base, lest it dissolve the seal and lose the vacuum.

Anybody else try this for "noisy" tubes?

[sleepysurf]

Hah! I just googled Caig and vacuum tube, and discovered they actually sell a "Vacuum Tube Survival Kit" with everything you need to safely clean pins and sockets! Looks like it's available online from various merchants.

[Myles B. Astor]

I haven't had any crackling/hissing with the 6N30p tubes in my CT-5.

However, a few years ago I had that issue with my Modwright SWL 9.0, which was "cured" by CAREFUL application of Caig Deoxit and Pro Gold to the tube pins. I made sure I didn't get any liquid where the pins enter the tube base, lest it dissolve the seal and lose the vacuum.

Anybody else try this for "noisy" tubes?

But I had issues with the 6H30s in my ART amp. They lasted six months before being to sound like static and turning a nice lavender color. Have ended up with some NOS DRs and no issues.

[watchdog]

I've had this problem with my Genalex reissues in my ET3SE too. Out of a batch of 4, two are too hissy. One was fine but noise progressively increased over the 4-5 months I used it. The last one is fine but has slight hiss in one channel.

Using my vintage tubes, most were simply too noisy. The worse was a Mullard that you could use as a karaoke mic. The only real quiet tube I have is the stock EH that came with the amp.

Interestingly, like Myles, one of my stock EH 6922 tubes (supplied with my Classic 60 SE), gave me the lavender colour show after a few months of operation.

Finding quiet tubes for the ET3SE is really a challenge. My speakers are 90db sensitivity. I wonder how people with even more sensitive speakers cope ?