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6922 Issues / Recommendations

I have a pair of Quicksilver Mid-Monos. After shutdown one of the amps produce a static noise through the speaker. Last night while shutting down in the dark I noticed some arcing inside the 6922 driver tube. I am assuming that this is the source of my problem.

My output tube are EH-KT88 and are about one year old. Based on past experience these tubes tend to last 2 years. The 6922 are the originals that came with the amp when I bought them new more than 4 years ago, they are Sovtek.

I guess I should swap tubes between amps to be sure to find the culprit. One more note, the amps play fine when on the problem only occurs after shutting off the power.

If my assumption is correct and I need to replace the 6922, what tubes do you recommend. Budget would be up to 100$.
nick_sr
13 responses Add your response
bojack
652 posts
 
Yank that tube and throw it away…do not use it in the other channel. Purchase two new 6922s. If same problem, call Mike and he will ask you to send the amp to him for repair.
jedinite24's avatar
jedinite24
1,503 posts
 
Hi Nick_Sr

I would contact the tube seller Jim McShane asap for help. The guy great with tube recommendations for gear. He handles new and old stock tubes. He's help me a bunch with preamp and power tubes for my gear.

If you can find them try Ediswan 6922 tubes from Upscale Audio. When I had a 6922 based tube preamp these Ediswan 6922 tubes added some nice sparkle and detail in the mids and highs in my system.
nick_sr OP
263 posts
 
I swapped the tube to the other channel and the noise followed. So I am sure that it is the culprit. Amps will remain off until I find a suitable replacement.

@jednite, my amp uses one 12ax7 as the input tube paired with one 6922 as the driver. I read in an older thread that this configuration has it own sonic signature that means that I will not likely hear the full potential of 6922 but a mix with sound of the 12ax7.

So I a reluctant to spend a lot on NOS tubes if I won't hear the difference.

Has anyone experimented with different 6922 on their Quicksilver Midmonos?
jperry
2,450 posts
 
Call Quicksilver. They will sell you the tubes for your amp at a reasonable price. Look at their web page for pricing.
bojack
652 posts
 
Nicksr,

It's funny that you ask because I just ordered a pair of RCA 12AX7As for my Mid-Monos. Mike at QS says that the input tube affects the sound more than the driver, so we will see when the RCAs arrive later this week. I have the very newest version, btw. If I cannot hear any difference, that will be that. However, if I can, I will play around a bit with the 6922s and test your theory.
mechans
3,048 posts
 
Jim McShane carries many of the Gold Lion re-issue tubes including the 6922 sub. The sound should be considerably warmer than the usual Sovtek although both are Russian, NOS 6922s are expensive and difficult to get reliably- but if you want to look at some Upscale Audio is a good place to check out. It is clearly truw that no one knows your amp better than Mike Sanders so his advice is invaluable.
oddiofyl's avatar
oddiofyl
3,883 posts
 
The Russian "rocket logo" 6h23n is a great tube if you can find them....rugged and sound great
ptmconsulting
1,000 posts
 
You can obtain the Russian Rocket Logo's directly from sellers on e-bay. These tubes are even better after croying (it smooths them out somewhat and they soound more open to boot).
nick_sr OP
263 posts
 
Thanks for the recommendations. In the end I heeded Bojack's, JPerry's and Mechans advice and I spoke with Mike Sanders.

I am really glad I did, he suggested that I change the input tubes as wells as the drivers. The end result was well worth the wait, everything sounds a lot tighter and more focused.
wrm57
1,048 posts
 
Hi Ptmconsulting,

Any suggestions on where to get tubes cryo-ed? I have 50 of those Rockets, more than enough for a few experiments.

Thanks.
facten
2,881 posts
 
So Nick what tubes did you wind up with?
ptmconsulting
1,000 posts
 
There's a ton of cryo places around. I piggy-backed on another local audiophile's order, so I don't remember the place we used.

I think the one characteristic you want to see in their process is a slow warm up, like over a 24 hour period.
wrm57
1,048 posts
 
OK, thanks, I'll poke around.
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