MOTM

I've had this idea for a simple-ish module going round in my head for a 
while. I suggested it to JLH as a poss stooge panel, but it fits in with 
the new micro range, AND, it's likely to be useful to any MOTM user as 
well. What I'm after is a single width panel, with 2 VCAs on it, so I 
thought I'd post it up here, to see if anyone finds it interesting.
  Now, the basic concept for each of the VCAs is similar to the "MVCA" 
function on the Korg MS20.  This consists of an input socket, and output 
socket, and a modulation input socket.  A CV signal of 5v at the 
modulation socket equals unity gain through the VCA, a CV signal of 2.5v 
equals half gain etc etc.  All very simple, but I would add a reversible 
scaling pot to the CV input, so one could control and/or invert the 
amount of modulation.  Turned all the way to the right, and given a 5v 
CV signal, you get unity gain, all the way to the left with a 5v signal, 
and you get an inverted version of the input.  I would also suggest an 
extra level of functionality, which is to use the switching function on 
the CV input jack. When there is no plug inserted into this, the module 
should function as a simple reversing attenuator.   Possibly one could 
add a toggle switch to the panel - either AC/DC coupling or 
Linear/Exponential response, whichever is most useful.  Obviously, the 
module would have the usual MOTM characteristics of low noise & 
distortion, extreme accuracy etc (the Korg circuit, where I got the idea 
from certainly isn't any of this  - IIRC, it's vactrol-based!)   I'm 
figuring that with 3 sockets, one knob and possibly one switch, 2 of 
these will easily fit on a 1u panel.  I'm always into efficient space 
utilisation!  Now, why do I think this is a good idea?  Well, firstly, 
for those who are building a system from the micro-module range, it will 
provide 2 VCAs in a compact package. Those of us who have larger systems 
would find this useful as an inter patch VCA, either for signals, or for 
dynamically controlling modulation depth - 2 examples would be LFO depth 
via mod wheel CV & filter envelope depth via velocity CV (this latter is 
offered on the Rhodes Chroma, and is very effective and expressive) at 
the very least, any CV input on the system could become an 
envelope-controlled CV input by adding this module to the chain. 
Anyway, I think this would be a simple, but very effective & useful 
addition to the MOTM range, and I'd certainly buy one.

-- 
Norman Fay