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This is for the amp in my latest build thread. It's a Cali mod 2204 using a Ceriatone chassis and turret board. But everything else sourced by me and the circuit has a few small voicing changes. But nothing major.
I've built 3 of these. They are all quiet except this one. The amp sounds great, tone-wise. But there is a slight hum. The hum isn't very loud. I can turn the master up to 100% and it's fine. But if I engage Bright 2 to either position the hum is amplified greatly. I've ruled out tubes as an issue. And I *think* I've narrowed it down to either the Bright 2 switch or Gain 2 pot. Lead dress doesn't appear to be an issue. I've moved things around and no changes. And the lead dress follows my previous builds and they aren't noisy.
The only things in the entire amp that make any sort of noise when tapped with a stick are V1b plate and V1b grid pins right on the tube socket.
Shielded wire is used for the FX loop, Gain 1 pot and a few other wires here and there where needed. Gain 2 wires are unshielded. But they're the same in my other builds that are noise-free.
I'm no tech. Just a hobbyist. So I don't have an o-scope. So if there's something I should check with a DMM, like DC across a component or something, that would be helpful. Otherwise, I guess I should try replacing the pot and switch.
Schematic: https://orig15.deviantart.net/ede0/f...lm-dbkjpxy.jpg
I've built 3 of these. They are all quiet except this one. The amp sounds great, tone-wise. But there is a slight hum. The hum isn't very loud. I can turn the master up to 100% and it's fine. But if I engage Bright 2 to either position the hum is amplified greatly. I've ruled out tubes as an issue. And I *think* I've narrowed it down to either the Bright 2 switch or Gain 2 pot. Lead dress doesn't appear to be an issue. I've moved things around and no changes. And the lead dress follows my previous builds and they aren't noisy.
The only things in the entire amp that make any sort of noise when tapped with a stick are V1b plate and V1b grid pins right on the tube socket.
Shielded wire is used for the FX loop, Gain 1 pot and a few other wires here and there where needed. Gain 2 wires are unshielded. But they're the same in my other builds that are noise-free.
I'm no tech. Just a hobbyist. So I don't have an o-scope. So if there's something I should check with a DMM, like DC across a component or something, that would be helpful. Otherwise, I guess I should try replacing the pot and switch.
Schematic: https://orig15.deviantart.net/ede0/f...lm-dbkjpxy.jpg
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