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Post by jhen86 (jordan) on Jan 1, 2019 9:49:27 GMT -7
Just had a mysterious hum start in my M12 head? Sounds like ground hum to my ears (down near 60hz). Odd thing is it was not there at my Christmas Eve gig last week, or at least not noticeable. Any ideas from any wiser gents before I start swapping tubes and checking guts? Could it be bad power at my house? A few other details: - Occurs as soon at I kick on the amp, even without guitar plugged in.
- Happens on numerous cabs.
- Does not happen with my RXJR head in identical scenarios.
- Has new/NOS tubes with very few hours (though I understand failures can happen anytime).
- I just did Doc's yearly amp maintenance routine on all amps this summer.
Thanks in advance for any input!!!
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Post by purpletele on Jan 1, 2019 10:11:14 GMT -7
Just had a mysterious hum start in my M12 head? Sounds like ground hum to my ears (down near 60hz). Odd thing is it was not there at my Christmas Eve gig last week, or at least not noticeable. Any ideas from any wiser gents before I start swapping tubes and checking guts? Could it be bad power at my house? A few other details: - Occurs as soon at I kick on the amp, even without guitar plugged in.
- Happens on numerous cabs.
- Does not happen with my RXJR head in identical scenarios.
- Has new/NOS tubes with very few hours (though I understand failures can happen anytime).
- I just did Doc's yearly amp maintenance routine on all amps this summer.
Thanks in advance for any input!!! You might have a loose control pot which is causing a hum. You may have gone through and tightened them, but if you haven't then you should try that. That is the most likely candidate. It could be a broken ground wire somewhere, this is a strong possibility and easy to resolve. It could be oxidation in the send and receive jacks even if not in use, but this is most likely not the cause. That's is my 2 cents.
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Post by DRZ on Jan 1, 2019 12:32:36 GMT -7
Could be a bad/weak/mis-matched EL 84.
Z
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Post by jhen86 (jordan) on Jan 7, 2019 7:40:55 GMT -7
Could be a bad/weak/mis-matched EL 84. Z The Doc is right once again. Popped a new set of el84s in and the hum is gone. I told my wife and she said, “Sure is nice being able to ask the guy who made it!” Thanks, Doc!!!
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Post by purpletele on Jan 7, 2019 13:21:28 GMT -7
Could be a bad/weak/mis-matched EL 84. Z The Doc is right once again. Popped a new set of el84s in and the hum is gone. I told my wife and she said, “Sure is nice being able to ask the guy who made it!” Thanks, Doc!!! Good resolution
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