Constant noisy tubes maybe go solid state?

One example, having a humming (unclean) coax cable from a cable TV company plugged into nearby boxes sharing similar or conjoined AC outlets on the same circuit back to the junction box can do this too.  Amps with big transformers can simply amplify this too, right to your speakers. Bzzzzzzzzzz. Many years ago finally caved and went to a dedicated AC circuit and power-conditioning station. Much better.  

Short story, using quality well tested tubes matters. Good matching of voltage/impedance between the preamp and amp(s) matters.  

Sure seems like there is something else going on here.  

Several colleagues with your same preamp with few issues like this. 

Sourced several tested and matched pairs 12AU7 and 12AT7 tubes from many of the same providers you have with minimal issues. 

A good tech?
Might be worth taking the amplifier and preamp to a good tech, checking with clean power and to confirm if any damaged occurred to the amp or preamp during all of these tests. Or, to at least find the real root cause.  Could save you a lot of time and $ too. Best of Luck. 

06-06-2018 5:23pm by Jackd
...As the Odyssey amps have low input sensitivities in the 1 volt range you need to be careful of tube preamps with high gain especially if your speakers have sensitivity ratings much over the mid-80's range.

Was member jackd on to something a few years ago, about pairing higher gain preamps with the Odyssey Khartago amp, 9th post down?

https://forum.audiogon.com/discussions/preamp-suggestions-for-hot-rodded-odyssey-khartago

So are you saying the QS tube preamplifier is working reasonably for yournow paired with your Odyssey solid state amplifier?

Doing some research on this the past weekend having gotten lucky with prior tube pre and SS amp combos along with tube amp combos, wondering what you might be experiencing. And, back to what jackd said, as you already know.  

The QS preamp is a "low noise" line stage preamp with only 100 ohm output impedance, 18db gain.  Your Odyssey amp apparently is more favorable when matched with preamps with no more than 14db gain. A notable output/impedance mismatch more than voltage.  So, I guess I sorta see why you would be fishing for low gain tubes on the preamp side. Your preamp is more ideal for good low noise tube amps, single-ended or ultra linear. When ready, down the road, and pending on your speaker types and efficiency, maybe try a good pair of mono tube amps with your preamp. Its a lot of fun. Good luck.  Look up impedance, matching too, not just voltage, gain.  

https://www.psaudio.com/pauls-posts/lowering-impedance/

@slaw
"Why not talk to Mike Sanders?"

@gochurchgo
... "Emails and voicemails unreturned. Sh*t service".

Really, no response ???

Mike at Quicksilver just emailed me back in 10hrs, on a Saturday weekend day mind you. Fast response. Use email.  

He’s fine, open for business and customer service. I shared some of you could not reach him. He wanted to know what the issue is and what its about. He said to call or email him. Try again. FYI: his contact page is UPDATED with the direct (gmail) email address listed, go to: http://quicksilveraudio.com/contact/

@gochurchgo

decooney 2 emails and 2 voicemail.
It’s fine. Things are running and I’ll be moving on the QS next year anyway.

Hmm. I did notice QS changed their contact page some. No more fill-in page. Shows email address only. He did respond back quickly though.

----------
re: old tubes - I do know people try different quality grade tubes in his preamps and the stock JJs he provides work well 99% of the time, functionally. Sure, others sound better and yet some old tubes from eBay and others with no reputable curve tracer or proven reputation and good results are a crapshoot. Can’t fake it on old tubes, as we all know too well. Best to buy from reputable tube resellers with real guarantees.

A friend had issues with his QS preamp as soon as he started "saving money", "getting a better deal" buying sh*t tubes off eBay. He's got good tubes now, all quiet again on the western front with his QS preamplifier. 

Selling it? If you decide to put that QS preamp up for sale, be sure to post it on Agon, someone here will grab it and make good use of it! Best of luck.

CONTACT Quicksilver,  go to: http://quicksilveraudio.com/contact/

Just chatted with Mike Sanders at QS again over email a few times.  He wanted to re-share he "responds to all emails" and suggested people may not be using the correct email address if they are not seeing a response.  

Note:  I checked and see his current gmail address via the "contact" page on his website is NOT the same as the old one some of us may have had last yer.   See contact on his site for the correct one to use.