1 Jun
2009
1 Jun
'09
7:01 a.m.
Looking at the schematics there is no evidence of any
'click removal' action. Also the waveforms summed there
(for 4',8' and 16') would not be sinewaves. Each divider
output has an RC lowpass filter before going to the mix
bus. Assuming the dividers generate square waves, the
smoothest waveform you can get would be a triangular one.
What each of these RC filters does exactly will depend on
the impedance it sees on the mix bus, and this is a complex
function of the drawbar positions (*all* of them for each
bus, since they share the resistors) and the number of
notes already on.
Nice information.
I never got to hook my Continentals up to a scope to have a good look at them but I agree
the sines were not all that pure so a tri would be possibly closer to the original than a
sine waveformed lookup table as used by Connie. I might actually give this a test in
bristol and see how its Vox sounds with them, it also uses similar lookup tables. It would
not be that difficult to fill them with heavily RC filtered square waves, even testing
with some different slew rates and see what effect that has.
Your comments on the drawbar effects are very interesting, I had never considered the Vox
to have damping as the Hammond did but I would definately believe it. Do you happen to
know if the schematics were from a Mark-I Jennings design? I would be interested in
modeling some of the resistor circuits as well.
Regards, Nick
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