2. amps-preamps
  3. 161387-96791

Constant noisy tubes maybe go solid state?

I have a Quicksilver Line Stage Preamp (12AT7) mated to an Odyssey Khartago Stereo. Overall I like it. Way too much gain but I digress. Weeks after receiving it I rolled in a few different tubes, kinda fun to color the sound signature. I liked rhe RXA black plates I got and those stuck around for more than a year. They started going microphonic and making noises so I ordered another pair (noisy) then another different vendor (blasts of white noise) and another set that arrived today (one is noisy as holy hell and one seems fine).

So where does one order preamp quality tunes that are quiet? Is there something I’m not requesting when ordering? Maybe dump
snd go solid state? I’m trying to be humorous because I’m pissed. Ha.
gochurchgo
gochurchgo OP
910 posts
 
Went and threw on the 12db attenuators I had and now everything is dead silent. All the tube noise I have been getting (which didn’t get louder with the volume pot) now gone below the threshold of the attenuators. I’m pondering snagging a 6db pair just to see what that does.

So by this, if I theoretically could lower the gain of the QS to say <8 FB gain then I should have no issues. Right? Or is it non linear and I’m over simplifying?
alchemyman
21 posts
 
Get some ECC83 JJ gold pins. Very reliable -- not expensive.  Mullard NOS are not bad, RCA clear tops. Tesla 803c in place of 12AX7 are nice, but hit or miss as to what you can find.

Try here:
https://www.amplifiedparts.com/tech-articles/12ax7-comparison-current-made-tubes
jackd
1,065 posts
 
@gochurchgo 

If the 10db attenuators work and don't effect the sound to your ears I wouldn't waste anymore money on attenuators.  If you haven't tried the 12AU7 tubes yet that might be a better avenue.  Also my personal opinion but if you want to continue to deal in NOS tubes without getting duds I would stick with Andy at Vintage Tube Services. There are still a couple of reliable dealers on Ebay that fully test and back their tubes but they are few and far between. 
gochurchgo OP
910 posts
 
@jackd  I’m so overloaded right now that I’m just leaving it so I can have a few minutes of peace and gear music. But to your point part of me agrees and part of me is disappointed that I’m selling this piece of gear short by using them. 
I’m not sure what I’m going to do. Early next year I’m hoping to replace my trusty Lounge phono with something better but that brings me to tunes again. Or maybe dump the QS and go solid state and save the new phono for 2022. 
Just trying to survive the world right now
jackd
1,065 posts
 
A guideline to what Klaus thinks is an acceptable gain tube preamp would be the Candela at 14db so with speakers of "normal" sensitivity the QS would be fine.  But unfortunately you bought speakers than don't fit in that definition so you are going to have to mitigate the situation for now unless you want to start selling and buying.  If for now the attenuators allow you to listen to your system with no appreciable loss of fidelity then resolve your tube vendor issues get a good pair of AT7's and let it be.  You can get a good and quiet pair of NOS AU7 tubes for not a lot of money but it won't be from the usual suspects like Kevin, Brent or Andy as I've done it recently.  Contact me by PM if you want to know where.
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