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05-28-2024, 12:57 PM
Hi Guys
The original form of the SV1-D is what I called SD-1, never released as such but I used it in my amps.
In that form, R2=56k2 and R3=6k81. This definitely does not go to zero volts out, but the amp sound would cut off right at the end of the pot sweep (values tuned by ear). When I decided to change the SV kits to this format for general release, the PCBs were labelled with these values, but later shipped with the newer values listed in post-1. Recent boards are labelled for the new values.
Note that a compromise with the top end dead spot is that if you try to eliminate it you may end up dropping voltage across the mosfets at the nominal full power setting of the Power Scale pot. Losing 10V or so in a 4-500V environment is no big deal BUT the mosfets will be running a lot warmer than they should at full power. Mosfet dissipation at full output should be essentially zero.
The original form of the SV1-D is what I called SD-1, never released as such but I used it in my amps.
In that form, R2=56k2 and R3=6k81. This definitely does not go to zero volts out, but the amp sound would cut off right at the end of the pot sweep (values tuned by ear). When I decided to change the SV kits to this format for general release, the PCBs were labelled with these values, but later shipped with the newer values listed in post-1. Recent boards are labelled for the new values.
Note that a compromise with the top end dead spot is that if you try to eliminate it you may end up dropping voltage across the mosfets at the nominal full power setting of the Power Scale pot. Losing 10V or so in a 4-500V environment is no big deal BUT the mosfets will be running a lot warmer than they should at full power. Mosfet dissipation at full output should be essentially zero.
