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9 hours ago
Hi Kevin,
Many thanks — that's very helpful and clears up the switching issue with the kit-version SV2.
I went back through the SV2-M36 notes after reading your reply. I think I may simply have been using different terminology for the Drive Compensation function.
My existing master volume is a Lar-Mar/type-2 PPIMV: dual 250kA, PI coupling caps to pot-X, wipers to the EL84 grid stoppers, pot-0 to ground as the amp is cathode biased, with 1.8M safety resistors from each wiper to ground.
Looking at the Drive Compensation circuit in the SV2 notes, it appears to be doing essentially the same job — a dual post-PI control varying the signal into the output valves. So am I correct that my existing PPIMV can serve as the Drive Compensation control, rather than adding a separate DriveComp pot?
If so, I understand the switching as four relay poles: one to short/unshort the added Power Scale resistance, two for the two halves of the PPIMV/DriveComp, and one to reduce the reverb level — hence two DPDT relays.
Thanks again for the quick help.
Steve
Many thanks — that's very helpful and clears up the switching issue with the kit-version SV2.
I went back through the SV2-M36 notes after reading your reply. I think I may simply have been using different terminology for the Drive Compensation function.
My existing master volume is a Lar-Mar/type-2 PPIMV: dual 250kA, PI coupling caps to pot-X, wipers to the EL84 grid stoppers, pot-0 to ground as the amp is cathode biased, with 1.8M safety resistors from each wiper to ground.
Looking at the Drive Compensation circuit in the SV2 notes, it appears to be doing essentially the same job — a dual post-PI control varying the signal into the output valves. So am I correct that my existing PPIMV can serve as the Drive Compensation control, rather than adding a separate DriveComp pot?
If so, I understand the switching as four relay poles: one to short/unshort the added Power Scale resistance, two for the two halves of the PPIMV/DriveComp, and one to reduce the reverb level — hence two DPDT relays.
Thanks again for the quick help.
Steve
