Not so deluxe. More like deFAIL.

September 13, 2008 3:25 PM

Guitar amp issues, with a long way between me and a tech. Help me know what to say when I call!

I've owned a Blues Deluxe reissue since 1996. Loved this amp to death when I first got it, and still do. I never gigged with it, just used it for practice and noodling. I put it in storage when I moved to an apartment in DC years ago, and now it's out of storage and I want to play it again.

Trouble is, when I turn it on, I get no sound. Often, the channel selector light will come on and a faint pop is heard. If I let the amp sit on standby for a half hour or so, I can play. Other times I let it warm up, and the minute I load the amp with a signal, it clips out on me.

I've fiddled with the tubes a bit, trying some replacements a friend gave me. I've also changed to fuse to no avail. This is my first tube amp, and only the second amp I ever bought, so I'm sort of a tube noob. There's no bias adjustment on this amp, so an old friend via email told me swamping tubes should be like changing a lightbulb.

Is my amp dead, or am I overlooking something?

posted by littlerobothead to sports, hobbies, & recreation (2 comments total)

From my husband:
that slight pop indicates a short in your wiring somewhere, and the fact that it doesn't always happen indicates it is an intermittent short, which swapping tubes won't help. take it to a shop and let them have a look, because it sounds like you may not be able to do too much about it yourself.
posted by kellyblah at 4:18 PM on September 13, 2008

Sounds more like a PSU issue to me (or possibly dud valves, but since you've tried swapping them, you can probably rule that out). The faint pop is likely due to the grid bias dropping too low as the plate voltage rises; the valves are then biased hard off. Likely the electrolytic caps in the PSU have dried out / unformed during storage. If they've just unformed, you may be able to re-form them by leaving it turned on for a day or so - if you try this, take the valves out while you leave it so you don't damage them or the speaker due to latch-up or oscillation.

Most likely, though, you'll need to take it to a tech to be repaired. It should be cheap enough to fix, but if you can find an old-school radio or TV tech who remembers valves it'll likely be cheaper than taking it to a specialist guitar amp repairer shop. Those guys are bandits... ;-)
posted by Pinback at 7:37 PM on September 13, 2008