Hi,
I was looking over the schematic of my Lee Jackson GP-1000 preamp:
https://imgur.com/JHtqvzS
I just discovered that the master volume is before the last tube stage.
Is it ok to put a Volume pot as the very last thing before the output jack, so I have control of the distortion of the last tube stage? Should I use a B1M pot? I won't be using a power amp, just running direct to analog cab sim.
I might need another cup of coffee but that Relay1 / SW1 arrangement puzzles me a bit..
As for V3A & V3B, they serve as respective output buffers..
Can't see any reason for Master pots transfer..
Quote from: Esppse on June 25, 2024, 02:37:14 AMI just discovered that the master volume is before the last tube stage.
Is it ok to put a Volume pot as the very last thing before the output jack, so I have control of the distortion of the last tube stage? Should I use a B1M pot? I won't be using a power amp, just running direct to analog cab sim.
The last stage is an AC-coupled cathode follower so you won't be getting any distortion from it, it's just a clean buffer, so it's really not worth putting a pot after it.
Yes you
can put a A1Meg pot after it (actually A100k would be better), but your output will then be high impedance and sensitive to hum, with no obvious benefit.
Also be aware that the cathode follower can put quite a lot of voltage down the cable to whatever you plug into it...
Ok thanks for clarifying what a cathode follower looks like and does! I'll probably just leave it then.