Hello friends I need some guidance please.
I've recently built an AB763 kit. It works really well, sounds great, it's dead quiet. I'm 99% very pleased with it.
The last 1% that's doing my head in is the guitar signal faintly leaking through to the speaker even with the channel volumes turned all the way down. It happens on both channels. I changed the volume pots, didn't help. They were very stiff and wonky so I thought that had to be the problem. But no. New CTS pots didn't cure it.
How is this happening on both channels?
I've pumped a sine wave into it, chopsticked the wiring, watched it on a scope, swapped tubes, tapped around the connections, checked solders, I can't tell how that little bit of signal is getting through. Please give me some ideas to try. I'm still new to amp building and finding this issue is eating at me.
I've recently built an AB763 kit. It works really well, sounds great, it's dead quiet. I'm 99% very pleased with it.
The last 1% that's doing my head in is the guitar signal faintly leaking through to the speaker even with the channel volumes turned all the way down. It happens on both channels. I changed the volume pots, didn't help. They were very stiff and wonky so I thought that had to be the problem. But no. New CTS pots didn't cure it.
How is this happening on both channels?
I've pumped a sine wave into it, chopsticked the wiring, watched it on a scope, swapped tubes, tapped around the connections, checked solders, I can't tell how that little bit of signal is getting through. Please give me some ideas to try. I'm still new to amp building and finding this issue is eating at me.
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