Re: [AH] Re: Interested in Trapezoid VCA PCB?
2010-07-26 by cheater cheater
Gotcha. Is there no way to "track the whole cycle"? I am assuming that the envelope is just a filter being fed by constant current, so maybe scaling that could work... But that's just my imagination D. 2010/7/26 <jhaible@debitel.net>:
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> You could certainly track the decay time, or the reciprocal of the decay time, > precisely with 1V/octave. But you'd never get the whole cycle to be a precisely > tracking oscillator, simply because the other times (attack, on, off) are never > exactly zero. To make matters worse (in terms of tracking), they partly depend > on each other. This, of course, is part of the charm of the VCS3 trapezoid, and > it took some effort to cover this realistically without copying the actual > circuit. :) > > JH. > >> With just the decay under voltage control, will it be possible for the >> generated wave to track the voltage like it's a normal oscillator? >> >> Regarding demos, it would be cool if you could show one where the vca >> is really pushed into coloration :) >> >> The sweeps sounded real cool in that mp3 :) >> >> I agree, it definitely would be cool to have VC of all parameters. In >> that case you could do several nice things: >> route one voltage to two parameters, one positively and one >> negatively, to change the pulse width or shape without changing the >> pitch >> route one voltage to all parameters, to simply change the pitch >> route one voltage to only several parameters changing the pitch and >> use a comparator to start sending voltage to other parameters starting >> some higher pitch. then you get normally tracking pitch but also you >> get nice timbral change >> >> Cheers, >> D. >> >> On Mon, Jul 26, 2010 at 07:36, JH. <jhaible@...> wrote: >> > >> >> I would think that since Analogue Systems makes their own EMS licensed >> >> Euro module that one would want to go further than just a clone. >> >> >> >> Firstly I would think that the vc decay being tweaked to respond to 1v/ >> >> oct would add functionality. Also something like the trapezoid polarity >> mod >> >> would be good to have. >> > >> > Pos and neg polarity is a must, of course. >> > 1V/Oct (or any other user-selectable) response of the decay time also. >> > >> >> The thing I've always wanted is VC on all the parameters, not just >> decay. >> >> Obviously that would alter any tracking one might achieve with just the >> >> decay but it would make for some interesting signals. >> > >> > I'm afraid it will only be VC Decay, and manually controlled Attack, On, >> and >> > Off Time. >> > Even though my implementation is different from EMS's - to avoid problems >> > with Ge diodes or leakage and SOT parts - that unique interaction of the 4 >> > time parameters, and the natural feel of the Off-Time knob turning the >> > repetition off towards the cw end, require it to be done that way. >> > >> > BTW, there will be an ordinary Gate input of course, positive Voltage >> > trigger and negative Moog/Korg Switch trigger. >> > Maybe I'll put in an "audio trigger" also, such that the trapezoid can be >> > started by a certain signal level, or sync'ed to the beat. >> > >> > JH. >> > >> >> > > > > > ------------------------------------------------- > debitel.net Webmail >