Microphonic tube or tubes?

headrott

OK, I'm tired so I hope this makes sense when I am done.:D

I recieved some tubes I bought from 2 different sellers the first set are Siemens CCa tubes and the second are some Siemens E88CC tubes. Both sellers claimed they were tested in a tube tester and for microphonics, etc. I switched out the Amperex Buggle Boy D-getter 6DJ8 tubes and I installed the Siemens this afternoon and turned on the BAT VK-3i. Started playing "Hidden treasure" by Traffic with no problems. I then switched to Robert Plant's Shaken N' Stirred and finally Plant's "Fate of Nations" CD. I played the first 2 tracks no problem. I skipped to "Memory Song (Hello Hello)" and the last part of the song the final note(s)? kept ringing through the speakers after the song ended. I got up and walked up to the CD player and stopped it. The note continued to "ring" through the speakers. I then turned the volume all the way down on the preamp and the "ringing note" stopped. I turned it back up and the not continued to ring. I muted the preamp and it stopped. Unmuted it and the note was still ringing. I finally shut down the preamp and waited a few minutes and turned it back on....No ringing.

I continued playing "If I were a carpenter" from the same CD. No problem. I played the bonus track "Colours of a Shade" and again toward the end of the song a note was ringing again through the speakers. I tried the mute with the same results as the last time. Volume...same. I then thought if it's a microphonic tube, when I tap the preamp case it should ring. I did lightly tap the case and sure enough one or more of the tubes made a ting sound. The ringing note stopped ringing. I tapped again on the preamp case and ting-ting again.

My question is: Can the audio from some speakers cause a microphonic tube to "ring" a note through it? I have never had a problem like this before and I have been using tubes for about 12 years now. Any help would be appreciated.

Greg

headrott

Keiko wrote: »

Yep. Had a similar problem with some Amperex 7062s recently. Some of the sweetest sounding tubes I rolled in my pre, but they got to the point I couldn't use them anymore. They'd howl at the slightest ambient noise. Fortunately, the polkie I bought these from exchanged them. Some tube dampers and isolating your pre might help. Good luck!

Yep, i have it isolated on some vibrapods and cones on a board. I do not have dampers though. Maybe it should be my next purchase. Thanks for your help.

Greg

headrott

Which version do you recommend (do you own)?

Greg

headrott

I think I will try the Ultrasonic 9s for the E88CCs and the Ultrasonic 30s for the 6V6 tubes. Thanks for the advice.

Greg

heiney9

What Keiko said .

Those series Amperex, Siemens are noted to possibly be microphonic something about the longer plates, yadda, yadda, yadda.

Which 6V6's are you using? Typically those don't have issues, especially the older RCA smoked glass. Microphonic tubes tend to be the smaller signal tubes, not always but a majority if the time.

H9

headrott

heiney9 wrote: »

What Keiko said .

Those series Amperex, Siemens are noted to possibly be microphonic something about the longer plates, yadda, yadda, yadda.

Which 6V6's are you using? Typically those don't have issues, especially the older RCA smoked glass. Microphonic tubes tend to be the smaller signal tubes, not always but a majority if the time.

H9

Hi H9,

I am using some Pope 6V6GT tubes I got from upscale audio. They seem to be very good. I did have some Amperex Bugle Boy D-getter 6dj8 tubes in there and they had absolutely no problems at all. I don't think it the Pope tubes because as I said, when I put the Amperex and Popes together theere were no noise problems at all. The Siemes CCa/E88CC and Amperex 6dj8 tubes have similar plate designs. Actually, the plates on the Siemens and Amperex tubes seem about the same length as the Sovtek 6922 tubes (maybe barely longer on the Siemens and Amperex). Certainly not as long as the RCA long black plate tubes though. I oredered the tube dampers lasat noght and they shipped today. I should get them by Saturday and I will let everyone know how it turns out.

Greg

heiney9

Rich (SCompracer) used the Pope 6V6's in his BAT pre at one time and he really liked them. I've almost pulled the trigger on those from Upscale a couple times for my office rig amp, but I really, really like the 50's RCA's and I have plenty (10 total).

If it's minor ringing the dampers will probably help. I had a pair of 1961 RCA 6211 (longer plate version of 12AT7) brand new and they howled like a coyote under a full moon. No amount of anything was going to tame those.

I know Mike never did get his 7062's to stop their microphonics. I have a pair of early 50's Ratheon 3-mica, blk plate 7062's that are dead quite. Go figure......basically an earlier version of the same tube Mike had.

H9

headrott

Yeah Brock, the Popes are very good. I have not heard the RCA gray plates though so I cannot compare. I will eventually get some though as I have heard they are very good. The combo of the Popes with the Amperex and Siemens tubes seem to work very well.

Greg

heiney9

Keep me on the list if you ever want to sell it. There was just another one on the 'Gon but, Summer is here and have some other projects that need funding currently and I'm enjoying what I currently have. But one of these days I'll pick one up.

H9

zingo

I have used the silicone ring style dampers on the glass itself, and dampening between the glass and the plastic bass. They are a good, low cost solution.

headrott

I recieved my tube dampers today and installed them into my pre-amp. I ended up using them on my Amperex D-getter 6dj8 tubes instead of the Siemens as I am sending the microphonic tube(s) back to the seller for a refund. Immediately after installing the dampers and sitting down to listen I noticed a pretty dramatic difference in the highs and lows. The highs are much smoother and have a less harsh sound when the "s" and "ch" sounds are played. I haven't played too much cymbal work yet, but I would guess they are going to be much better as well.

The bass is substantially tighter now and does not linger as long after the bass notes hit. I can notice more details in the music as a result of this. The imaging is much more distinguished with much greater dispersal and separation of the instruments and voices as well.

All this came as a result of only adding the dampers, and I have only played about an hour and a half worth of music so far. I don't think they are broken in yet. I can't remember the time that was recommended for them to break in, but if they made this big of a difference already then it should be great when they break in all the way. I now am wondering what took me so long to buy some tube dampers being as I have been using tubes for about 12 years and have not tried any until now. Thanks Keiko for the recommendation, it definately made a difference.

Greg

headrott

The combo of tubes and vinyl is analog bliss. Granted, potentially noisy analog bliss but you cannot beat the tones you get with them mixed together. IMO much better than anything digital. It's kind of like comparing the tonal qualities of Jimi Hendrix's guitar sound and style to Eddie Van Halen's. Sure, Van Halen's is faster and more detailed but Hendrix's guitar playing has much more nuance and feeling to it.:D

Greg