Is there such a thing??-- Tube Preamp Question

Wow, you have a lot of speakers! From the spec’s on the speakers and the Amp I would guess that the greatest noise issue would develope when you are using the Spatials. Very high sensitivity amp (2.9v) coupled with high speaker efficiency (95db) would probably operate best with minimal to no pre-amp gain. (Contingent on a lot of other issues of course). The other speakers should be less problematic, but never the less still need less fixed gain. All depends on your pre-amps minimum fixed gain as well as the input from your sources and how much attenuation you apply to this signal via you use of the VC on the pre-amp. At a minimum I would set the pre-amp to its minimum setting as suggested by Lowrider.

BTW, while I doubt that you would be guilty of this, do not judge your pre-amps ’quietness’ by just rotating the VC to max and putting your ear in front of the tweeter. That will always result in a worst case scenario and create unnecessary angst. Just select an input and set your VC to produce the maximum volume you would use. Then mute your source and the residual noise you hear is really all that matters. I think an ear about 3ft from the speaker would be a good distance to judge noise, although some even go so far as judging from the listening position.

BTW, tube life - if you are using low noise tubes appropriate for the pre-amp (Some pre-s are very hard on less than ’rugged’ tubes but other than that you should expect at least 3000 hours or much much more).

FWIW finding a good used tubed pre-amp for $2000 should not be at all difficult, but from what I’ve read about your’s I’m not sure how much you would improve your situation. I would look for other cures first.

Once again I'm in total agreement with newbee. That's a well regarded preamp, I would not be looking to ditch it. You've had it serviced and there is no hum present. 
This won't solve your problem, but order some NOS tubes; matched and tested for noise and microphonics. You'll have a lower noise floor and improved sonics over the EH tubes.
It's possible one of your tubes is microphonic. In this state, the preamp can pick up and present all kinds of crazy sounds. It's like having a microphone in your system.

Your TV uses a SMPS, a switched mode power supply, which often adds noise to your AC line and into the audio signal. I suggest unplugging the TV while you do some troubleshooting.  

Are all your components plugged into the Furman? Are you using a shared AC line that also has lights or dimmers on it?

This is an interesting question. I'm a newbie too so please forgive me for this stupid question: but do these issues occur in solid state preamps? The reason I'm asking is because I'm about to get a new preamp (my first tube preamp) and I hope I don't have these issues. I prefer low maintenance equipment so this better not happen. If so, I'm going back to SS! 

Hi birdfan,

While I can’t speak about your specific equipment, I can say a bit about tubes. EH makes at least two models of 6922’s and they both should last you for years. The 7308’s are the  Cadillac of the 6DJ8‘s  tubes  and therefore are priced  accordingly.  They don’t last as long as the 6922’s but will sound the best of all the  6DJ8 line.
 As for possible monophonic problems, have you ever heard of tube dampers? Just a thought.
BTW, what were the stock tubes  that came with your preamp? 

All the best with your journey.

JD

Hi blueorion,

I’ve used mostly tube equipment for decades and have never most of the issues mentioned above. The best part of tubes is you can change them in and out to other brands and types and get different sounds from your equipment. With SS you need to change the equipment to change the sound. There are other things you do to change the sound in both, but that’s for another thread.

All ll the best.

JD