Ampeg B25B - again
Moderator: jingle_jangle
Ampeg B25B - again
I've been messing with this amp for a year now and it keeps getting better . Replaced the volume pots and the 2 large filter caps . Channel 1 works great but when I turn the volume off on channel 2 it hums . If I turn the channel 2 volume up just 1/8" the hum stops ??
It's too early in the morning to talk about our relationship !
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soundmasterg
- RRF Consultant
- Posts: 1921
- Joined: Tue Oct 01, 2002 1:06 pm
Re: Ampeg B25B - again
I'm guessing the two channels are out of phase with each other and when turning up one channel or the other things are interacting enough to reduce hum. I'd have to look at the schematic to be sure and don't have the time right now. (Sorry)
Hum can be troubleshot using a stage isolation technique, but it would require an oscilloscope and a signal generator, and a DMM, and perhaps some chopsticks. If you knwo what you're doing with amps and have the tools, then you can figure it out. If not, then better be safe and take it to a tech. On the other hand, it could just be a bad tube too...
greg
Hum can be troubleshot using a stage isolation technique, but it would require an oscilloscope and a signal generator, and a DMM, and perhaps some chopsticks. If you knwo what you're doing with amps and have the tools, then you can figure it out. If not, then better be safe and take it to a tech. On the other hand, it could just be a bad tube too...
greg