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Hi Folks,Having bought my first tubed preamp almost a year ago (and living happily I might add) something weird has happened. Up until yesterday the pre had been quiet as a mouse. Now, all of a sudden, it's acting like a big LP cartridge and picking up any vibration. A little tap on the surface of the pre and it sounds like I'm tapping a needle. The thing is that it is suitably isolated on BDR cones and I don't think too much is getting through. The only noticeable sounds are when I tap on it.
Given all of that here's the rub... (and here's the really weird part) It is now sounding better then it ever has. The microdynamics are stunning. The "air" and "openness" are unbelievable. But there has to be something wrong and I'm afraid that one/two/all of the tubes is/are going the way of that damn dodo.
My questions to this venerable forum are: should I change it? Do I risk damage leaving it (remember - awesome sound)? Have they just finally worked into this stage and I should just shut my mouth, listen and be happy?
Any insight would be appreciated!
Thanks,
Jeff
PS - The tubes are JJ ECC82(x2) and ECC83(x1) in an ASL AQ2004DT
Follow Ups:
of an audiophile friend who listened very happily to his tube pre for years and years. Tubes wore out so he had them replaced. The "air" and dynamics were gone, all that. So he started tube rolling to no avail. Had a friend come over and listen to the old tubes, which he still had, trying to discern why no tubes (including same make and brand) satisfied compared to the very worn tubes. The other guy tapped on them and they were severely microphonic. So he actually called up a tube dealer and ordered microphonic tubes and lived happily ever after. Not a "great" story but interesting.
I must confess, I was smiling as I was reading post thinking you have a microphonic tube. BTW some would claim microphonics is one of the reasons why tubes sound better (and turntable cartridges too).Anyhow I digress, you probably have nothing more than a tube that has gone microphonic. If it is one channel only try swapping tubes to isolate which tube is the problem (rubber O-rings might help tame the problem and a chop stick to tap on the tube will locate it). But maybe this is a good reason to move up and hear some better tubes? Have you ever heard names like Mullard, RCA, Telefunken, Brimar, or Siemens in your sleep?
Known name brand NOS tubes are no guarantee of no microphonics. I have just purchased a pair of 1960s Siemens CCa, and one of the tubes is microphonic right off the bat. I also auditioned a pair of Amperex 6922 PQ Pinch Waist tubes that were both microphonic. $400/pair for each of these.I have to say, the image was stunning with these microphonic tubes.
Crazy, huh?
I am new to tubes but at that price I would think that they would be a matched pair and would have to be tested to be thought of as a matched pair. Wouldn't the testing process show that they were microphonic.
Yes my RCA/Siemens 6922's went microphic some time ago. If your 6922's aren't microphic they will at some point. Thats why they invented tube dampers. They work. Don't hesitate to use them.
I own Herbie's tube dampers and had them installed on both my microphonic CCa and Amperex Pinch Waist tubes. The tube dampers didn't solve the microphonics.
Try some vibropods under the unit. Anything to isolate the unit from the environment will help.
Thanks. I use Symposium Rollerblocks Series 2+.
Hi!Amazing...3 years ago since I changed the Chinese provide 6DJ8 tubes on my ARC-SP-9 Mk/2 hybrid preamp by Amperex Jan USN white label & gold coated pins 6922, & till today NO microphonics at all...my ARC is stacked on my McIntosh MR-78 cabinet fitted tuner on top of 3 Vibrapods Cones...NO minor problem since i changed the supplied Chinese tubes and I listen 12 hours EACH day...7 days each week. BTW...I'm a pensioner 63 years old...all the time at home...so I can enjoy turntable & radio or Cd player a lot!.
Could be that ARC is better designed & or built that your tube preamp???
" The "air" and "openness" are unbelievable."One of your tubes has gone microphonic. The added "air" is distortion. But if you like it, you like it.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
I have a balanced line stage using 26 DHTs. These, despite various mumblings from users, are not microphonic. I just swapped in a pair of 31 in one channel. These without question ARE microphonic. One rings to C and the other to D an octave down. But that's just if you tap them. In practice, I can hardly hear the difference. There's no hum with DC filaments and both sound great. Figure that one out.
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