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|previous: Carlos I've just had a look at
|4/28/2000 8:43 PM|
|JaySG||Re: Power Scaling in London Power amps|
I think it's done with a custom PT which has a variac-like
secondary section. Minimum might then generate 300Vdc and
maximum might generate 450V. The bias runs off of a
tracking voltage regulator scheme. Filament voltage(s) don't
change with level, so all is well there.
I built an amp which didn't put out the power I expected, so I added
a 60V DC power supply to jack up B+. Bias switches on a different
section of a DPDT. I don't touch it with the amp on, whereas the
built-in-variac would work that way.