Dual Timbre Modulator planned

Haible_Juergen#Tel2743 HJ2743 at denbgm3xm.scnn1.msmgate.m30x.nbg.scn.de
Thu Aug 31 19:24:00 CEST 1995

Ok, I am convinced now that I need a Timbre Modulator
in my Modular.
I'll use the Electronotes design, but I'll make some changes.
As the TM is supposed to act like a filter (well, of course more
the opposite of that), I'd want to use it on two VCO's simoultanously.
What I plan to build is a dual version that share all controls:
Stereo pots for the Shape knobs, 2p1t switch for Input Mix and so
on. The OTAs will be 13600 for matched gm, and they will share one
CV adder and one DC Adjust pot. Just want to have everything
in parallel. Some might object that there is more control over
the sound with two individual TW's, but then again my "Stereo"
one almost only requires the front panel space of a single one.
I'll even mix the two outputs together; so I can feed a VCA with
a single input without an additional mixer.
Using two OTA's I have to change the CV circuit a bit; I use the
standard OTA-controller circuit with opamp + pnp.

at last, a QUESTION to the Timbre Modulator gurus: I am not
sure if the DC Adjust pot should be a trimpot or an actual
front panel control. Is it just for "adjusting" the proper bias point
(as the name suggests), or is it a real tool for sound shaping
with more than one setting being of value and interest?

ah, and a second one: As the opamps are supposed to
do some intended clipping of the signal: Should I use exactly
the ones specified, or will TL074's work as well?
(I know they will *work* somehow; but does it have major
effects on the sound?)



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