I have an early 70's silverface v4-b head that, when I was playing it last week at practice, ran into some problems. Just so you can get an idea of my setup, I play an '86 mij fender contemporary strat, through a tech 21 double drive pedal, and a fender 412 cab. So anyway, it started making this popping sound, so thought it was the cables I was using, but that turned out not to be the problem. The sound it was making was a hiss (like what it sounds like when you have too much overdrive) that would build up, and then break, and each time it broke, and made the popping sound, the power tubes would flash blue. I haven't turned it on since then, I'm afraid it might just get worse. I had it serviced about 6-7 months ago, with all new capacitors and pots cleaned and such, except tubes, since the tubes were tested, and rated at about 98 percent, however they are the same tubes that were in it since I bought it about 4 years ago. I don't really know how to work on tube amps, and I'm working on a skimp budget these days, and my band is about to leave for tour on the 18th, so if I don't get this fixed before then, I have bigger problems. Any advice will help. Thanks!
Well it sounds like you just have bad tubes. 4 years is a rather long time to have the same tubes in an amp. Youll need to test the tubes, turn on your amp, turn up the volume slightly, turn off the volume on the guitar and tap each tube with a pencil. If you hear the tapping through the cab you have bad tubes. Also the way your tubes are "flashing blue" is a pretty good indicator. Its not super expensive to change out tubes, it'll probaby cost you about 100 bucks.
change the tubes. awesome amp btw.
My Fender Pro Jr does that. I need to figure it out. I replaced the EL84's a while back, so I hope it's the 12ax7's.
sweet, thanks for all the input! I'm glad it's not something more major. Do you think it could be just the preamp tubes? or just the power tubes? or all of them?