Help! Channel 1 on my Quad stopped working

Help! Channel 1 on my Quad preamp stopped working. All the lights look correct to me, and channel 2 works just fine. Unfortunately, I love channel 1 so much, and I'm don't care much for channel 2. I probably should have bought a studio preamp instead. So I HATE not having my Channel 1 right now!

I bought this about a year ago and had it shipped direct to the Mesa factory for them to inspect it and clean it up. They found no problems and did a general cleaning. It appears to be in pristine condition!

More recently, I just installed all new Mesa SPAX7-A tubes about 3 months ago, and I haven't used it a whole lot since then (just a few hours a week). And everything worked great.

Then a couple of days ago, i turned it on and channel 1 wouldn't put out ANY sound (lead or rhythm), while channel 2 (lead and rhythm) works great.

Any ideas about what could knock channel one completely silent (lead or rhythm), but leave channel 2 completely working?

Thanks!

Rob

Probably a faulty tube, check every one except for V13 wich concern only channel 2.

faulty tube would be my guess too. unfortunately, buying new tubes isn't always a guarantee they are fault-free.

Thanks for the suggestions! Tomorrow (Saturday, 1/2), I'm going to try switching some tubes around and see what happens. I'll report back what happened!

That was it! I simply switched a few channel 1 tubes with channel 2 tubes... and my channel 1 came back. I'll be ordering more tubes soon, then searching and replacing the 1 or 2 bad tubes. Thanks for your help!