Hum only at max
Moderators: pompeiisneaks, Colossal
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sluckey
- Posts: 3528
- Joined: Sun Jul 22, 2007 7:48 pm
- Location: Mobile, AL
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Re: Hum only at max
You put your NFB switch right next to the input jack! THAT'S A HUGE NONO!!! Move that switch to the back panel or just eliminate it. Then try to clean up your grounds.
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Stevem
- Posts: 5144
- Joined: Fri Jan 24, 2014 3:01 pm
- Location: 1/3rd the way out one of the arms of the Milkyway.
Re: Hum only at max
Also check where that feedback wire goes.
Getting a hum on that when you probe around should not be.
Do you possibly have it connected to that gain stages grid and not the cathode as it should be?
Getting a hum on that when you probe around should not be.
Do you possibly have it connected to that gain stages grid and not the cathode as it should be?
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
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audiosalvage
- Posts: 77
- Joined: Sun Feb 04, 2018 8:29 pm
1 others liked this
Re: Hum only at max
I removed the NF switch for now and put a switchable cathode cap mod in its place, moved the bias resistor so it's not crowded. Amp is quiet and stable throughout the pot ranges. I might just live with that. Thanks Gents.