Hi Folks,
I got a Blues Jr for several years. It has been my main gigging amp although I don't gig so much anymore. Got JJ's on it. Gorgeous sound!
2 weeks ago I went to a recording session. Once the amp was set in the recording room I started to warm up a little. After 30 min, a loud BUZZ started (PAWWWWWWWWWWWWWWWWWW) that wouldn't go away reducing both master and volume knobs and even plugging out the cable. Turned the amp off waited a little, powered it on again and after a few chords PAWWWWWWWWWWWWW again. I Looked at the tubes and they were glowing normally. No red plating, etc.
Then I sent the amp to a very nice local tech. We managed to reproduce the problem and while the Buzz was on he touched the power tubes, move them a bit on the sockets and the buzz went away. he said I got a possible problem in the sockets solder joints or even in the tubes. He played for a while after this and the buzz didn't come back. He did a resoldering job on all sockets pins, and sprayed some contact cleaner. Then we played for about an hour with no issues. I went home certain that my Blues Jr was back on the road again.
Yesterday I decided to test it at home. Played for 3 hours with no problems. I decided to take a break and put the guitar on the stand while keeping the amp on.
I was in Kitchen when all of a sudden I heard it again PAWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWW
I didn't believe!! The buzz was back! Turned it off, then turned it on again and the bus went away as for magic.
Played a little more this morning with no buzz coming back. It seems that now the amp in not as sensitive as it was before but I can't rely on it to record or gig anymore.
I heard somewhere that a bad speaker connection could possibly cause this. I compared the the plug pressure on the speaker jack against the footswitch jack and it seems the footswicht has a tigher connection.
Other than this, could it be simply a bad tube?
Thanks in advance for reading this long post and I hope somebody could shed some light on this issue.