Hi Decware Denizens,
I hope all is well with everyone. Having an issue with my wonderful Zen Ultra preamp. After being on sometimes for a short while and sometimes for several hours a hum begins to develop. I have traced the problem to the 6N1P tubes. I have swapped them around in multiple configurations but the problem always returns. It can be tamed by reseating the tubes but again, it always comes back sooner or later. Any thoughts? Tubes themselves, socket(s), or something else?   Thanx for any help or insight!
                   Best Regards, Mike

Hi Mike,
Having the same Ultra pre-amp, I do have a couple questions.  When you say you swapped the input tubes around in different configurations and the problem returns, are you swapping them within the same channel (i.e., Fronts, Rears, or Center/Sub)?  As you know, the Ultra is comprised of three discrete pre-amps so I'm just trying to get a better sense of how you are troubleshooting this with regards to isolating the bad tube(s).  That being said, if you are placing the tubes in different channels, is the hum moving to the corresponding set of speakers relative to where that input tube is placed?  Or, is the hum always coming from the same speakers, no matter where the tubes are being placed?

Another thing to note is the Fronts channel does go through the Mix channel tubes so be mindful as you move the input tubes around. Those two input tubes above the Mix knob (far right side) could create audible issues in your two front speakers.  .

Addendum:
Jeff, the problem does not show up in separate channels no matter how the tubes are swapped. Strange stuff. Cheers!

Will the zen ultra work with a streaming device? The hdmi sound will have to be converted to analog. Or does the hdmi plug into the tv and then connect the audio from the tv to the ultra? Just trying to wrap my head around it. Most of my video viewing is from an Amazon fire stick.