I've been wondering about some of the claims made about
Vactrols lately and it's starting to sound a bit 'mythical'. A vactrol is
simply a resistor and cannot colour the sound of something going through it, I
would imagine they would have less colour than just about any VCA out there. It
seems the appeal of vactrols is the sloppiness of the LDR when responding to
CV, surely you could do anything a vactrol circuit can do using a vca (and
perhaps filter for LPG) and a slew limiter to add sloppiness



I'm probably wrong but looking at the circuits I don�t see what 'ringing'
vactrols could actually mean beyond slewing the quick input trigger, something
any VCA could do.


Sean


To: Doepfer_a100@yahoogroups.com
From: zaum@...
Date: Tue, 8 Nov 2011 04:48:04 -0500
Subject: 1 Re: Buchla Bongo




























I remember this thread came up some years back. The Doepfer Low Pass Gate will get you something but it does behave slightly differently from the discontinued Plan B Low Pass gate and some of the other ones out there. In "Both" mode you still get a dampened sound with the vactrol decay. I guess the thing is as far as I can tell is that some other LPGs have things tweaked to emphasize the decay much further and have a both mode that decays longer. One might think that an envelope tweaked differently would make the Doepfer sound closer but the effect is different. This would be because the sound is the LPG's behavior once the CV has closed it. That's different from CV-ing the release longer. So my conclusion would be you'll get that type of sound but a struggle to really nail a very specific sound.



As for other details, it is correct that you want a rich enough sound to hear the lowpass effect well and you usually send it want amounts to a trigger pulse, not even an envelope. The vactrol's short attack and long decay creates the envelope effect.



As for the wavefolder connection. IMHO that's another recreation attempt issue. The Buchla 259, perhaps the most expensive and one of the most legendary VCO out there as well as the Music Easel VCO and different sounding 261e use a wavefolder as a timbre shaper. Given that the Buchlas were making "Buchla" sounds years before it's release one can conclude that a wavefolder is part of a more specific recreation of say a 259 or a Music Easel.



nick
















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