Tube Compressor Problem

[Rope]

I have an ART Levelar tube compressor pedal that works fine when you initially plug it in - noise free, etc. The output, however, gradually fades over time. If you play for an hour, it might only be a 1/4 the original volume.

Any ideas on what might cause this? Is it as simple as the tube beginning to fail?

 

[The BurgerMeister]

niftydog may attack me for jumping to conclusions here (), but change the tube(s) out! based on your description of the issue (and without knowing everything), i'd say that's the problem. if you change them out and it still does the same thing... well...

 

[bongomania]

+1, since that's the easiest part to change. If no luck with a new tube, then I imagine it could be a failing capacitor almost anywhere in the circuit, or possibly a problem with the power supply. Maybe try using a different power supply (with the same ratings) before desoldering anything.

 

[niftydog]

How old is the unit? Can you see the tubes glowing when it's on? If yes, turn it on cold and watch the filaments start to glow, take note of how bright they are, then wait for it to fade significantly and take another look at how bright they're glowing.

It could be tubes, it could be heater supply, it could be bias (I guess.) Easiest to check for is the tubes, so swap the tubes for new ones like everyone has already said. If that doesn't work, then at least you've got new tubes!

niftydog may attack me for jumping to conclusions here ()...

No way man, you're comment in the other thread re; line level was a good thought, it was the fonz's reply that worried me - like "Hey, the oven's really hot... hmm, must be the Turkey!" I'll leave the rest for the other thread though!

 

[The BurgerMeister]