2. amps-preamps
  3. 159694-100164

Balanced Audio Technology MK-30 tubes. Alternative to Sovtek 6922

I just picked up a MK-30, that had been checked out at BAT in 2017 with a clean bill of health. Receipt says "clean and clear".

But on my efficient Tekton Moabs, the tube noise is very audible at the listening position. So much so, I can not use this preamp. I am debating on just reselling it, or trying new tubes to see if the noise goes away or at least down. The Sovtek 6922s are now hard to find from any reputable source, what is a good alternative. I don't need the best fanciest NOS tubes, just a good solid performer.

Any suggestions?
128x128brad1138
brad1138's avatar
brad1138 OP
72 posts
 
Well, new tubes fixed the "tube noise issue", but revealed an intermittent crackling in the right channel. Excuse me while I go bang my head against the wall..... The seller actually left a receipt in the box that shows it was in for service at BAT in 2017 for EXACT same issue, but BAT could not reproduce problem.... The guy I bought it from bought it from the guy who had sent it into service.

The crackling is similar in volume to just under a normal talking volume...

https://www.youtube.com/watch?v=uWGGgaXMhd4
jond's avatar
jond
5,845 posts
 
Brad in your vid the crackling stops after about 30 seconds,  is it there when you turn the preamp on and fades away? Or does it keep coming back?
brad1138's avatar
brad1138 OP
72 posts
 
I just stopped recording. It is intermittent. Worse for the fist 10 to 15 minutes or so, but continues on after that. Might crackle for a couple seconds every few minutes after an hour or so. The guy sad I could have my money back with the tube issue. I am going to put the original tubes back and get my money back. I do like the sound a lot (when it is not crackling), I will keep the new tubes and look for a BAT of similar vintage.
jond's avatar
jond
5,845 posts
 
Brad I would say that's a good idea nothing worse than an intractable problem that's tough to track down. Good luck finding a new preamp!
More to discover