PrimaLuna tube amp issue


I just received by mail a used PrimaLuna Dialogue Premium HO Integrated amp. I hooked it up and it sounded great but after about 45 minutes of listening, the right channel disappeared after a quiet pop.  I have swapped out speaker wires, effect. No bad tube lights come on. Left channel plays fine. Headphone only has left channel as well. It was running a little hot, but not excessively so. Any thoughts...


Bummer way to start with a new/used piece of equipment....sigh.


Thanks for your help in advance.



hi, yes, I swapped all tubes from right to left channel. No impact. But,before I swapped I noticed a very faint amount of sound from left speaker at higher volume. Basically, still at square 1....




Ah, the joys of ownership of tube gear with high internal voltages! I assume that the main circuit fuse isn't blown as you still have a working channel. Unplug the amp and let sit overnight. Then remove the bottom cover and take a look inside. Look for a blown cap with stuff coming out of one end. Could be a blown coupling cap. If so replacing it may not solve the problem! I wish all tube gear manufacturers would provide schematics to make troubleshooting easier! 

Maybe swap the LHS with the RHS speaker wires.
If the bad channel moves then swap the interconnects LHS with RHS.

If the bad channel stays put, then it is you speaker.

All tubes including signal tubes? or Just the power tubes?

Are the valves lighting up? If they are not lighting up, that's one thing. If they are I'd be looking to the small valves.

Speaker wire swap to check for speakers.

RCA/XLR swap to check for cables and source.

Not a fuse in the speaker?

Not a fuse per channel?

Side Note: It was shipped to your Island.
Tubes 101 IF the valve survives transportation, it should be checked, WHY? That is when they WILL fail, most often after being shipped. Small valves???

Just thinkin' out loud.

Happy hunting

Yep, tube failure just after shipping, not unusual, and can happen with all tubes and equipment! This actually happened to my PL Dialogue Four, one EL34 power tube failed on first firing, took out one resistor on auto bias board, I did diy repair.

I have a PL HP, and had a channel go out.

Each channel has an auto bias board- could be the problem.

Time to send it to a PL authorized repair facility. Just any repair facility won't do-they will not be ablt to get the schematic. Call Call Upscale for reference.

Did you reach out to the person you bought the amp from?  Does it have any known issues?

Either send it in for a repair or find a local tech  does not sound like a major issue



Hello all, thanks for all the feedback. I reached out to previous owner and he suggested, as a number of you have, to touch base with upscale audio. I have made contact and they are walking me through a series of steps via email to close in on the problem. At this point, we are at the thorough check of tube point and will likely progress from there. If all these tests fail, I suspect he may have me take a look inside to see if there is any obvious damage. 

If anything significant pops up may return to this tread. Thanks again...

That is a heavy well built amp.  I owned one. 

The sound you describe hearing right before the issue in the one channel happened was a soft pop, which is making me curious to hear what Upscale says.  I had a couple of small issues like this and they were fantastic.  The problems were solved with no stress on me.  

Keep us posted as to what unfolds.