Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: jewishjay on April 09, 2026, 10:57:47 am
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I'd really appreciate you guys looking over my plans before I begin. Scratch build of a modded Deluxe Reverb AB763. My goals for this build are....
1. "Voxy" sounding normal channel
2. Verb and Trem on both channels
3. Add a master volume
Can you tell me if I've made any serious errors? If one of these mods clashes with another? I drew the type 3 post PI MV because I wasn't sure how a pre Pl MV would play with the pull down effect of the LDR.
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Hi, I can’t speak to how those two channels are mixed, but i think that 470pf cap in parallel with the 470k on channel one will bleed off high frequencies from channel two depending on where the volume pot of channel one is set.
My suggestion would be to use a single oscillator bias trem circuit like The princeton reverb, since you’re using 6v6’s and then you can buy an extra triode to buffer channel one’s tone stack. Then you can use 220k mixing resistors right before the 3.3M resistor. channels would be buffered from each other. Each channel would have this: Tonestack>triode>coupling cap>220k resistor then come together at 3.3M resistor. Just my two cents.
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Meant to say “single triode” oscillator circuit.
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that 470pf cap in parallel with the 470k on channel one will bleed off high frequencies from channel two depending on where the volume pot of channel one is set.
"It's not a bug, it's a feature." That's something people love about the 5E3 Deluxe, or the 1987 Plexi. Using the off channel knobs to make fine adjustments.
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Ahh. I looked the Plexi shcematic and see what you mean. I'm familiar with the 5E3, but never saw the cap in parallel with a mixing resistor like the Plexi. Thanks