MOTM

> From: "Paul Schreiber" <synth1@...>
> 
> 1) It's easier to design a linear VCA. *Much* easier!
> 2) For volume level-type apps, you want an exponential
>    response. But if the CV is expo. (ie an ADSR) then 
>    the VCA can be linear. (log x linear = log)

OK, I got that.  That's the MOTM way CV is expo and VCA is linear (ie
expects a expo CV to have a linear response).  Right?  So, I would call the
input on the MOTM-110 expo.

> 3) Log on a VCA is good for percussion (log x log =
> quadratic response). You get "Super Attack Transients"
> this way.

OK, so if your VCA was designed to have a expo curve (ie expecting a linear
CV) and you fed it a expo CV from your EG you would get that quadratic
response.  That makes sense.  So this is one good reason to have a "linear"
input on a VCA. You could put expo voltage to it for this effect.

>  Also, if you CV source in linear (say, a foot pedal)
> then for volume apps you reverse the symmetry 
> (audio goes into Log in, CV goes to linear in).

OK.  Got that, anytime you have a linear CV source.....

>From: "Tkacs, Ken" <Ken.Tkacs@...>
>
> Same goes for a VCA. It's usually cheaper and more
> direct to design an amplifier that responds linearly to
> an exponential control contour, especially since ADSR
> envelopes are usually created from charging capacitors
> which tend to exhibit the exp. curve anyway.

Right, the MOTM way.  But instead of cheaper, I'll substitute "more
efficient."  :)

> However, let's say you want to use the VCA to control
> something other than an audio signal. What if you want
> to use a CV to control the gain of another CV, in other
> words, use the VCA as a voltage-controlled resistor? 
> Then you most likely will want to use a linear CV in
> and a linear response to it. 

Ok, I understand the concept of linear + linear = linear.  But,  The
MOTM-110 does that with a "expo" input since the 110 is linear in response.
 Right?  So if you put a linear CV into the MOTM-110 you would get a linear
output.  If you put expo in you get an expo output.  Maybe terms is where I
am getting messed up.  I am calling the MOTM-110 CV input expo since that
is the voltage it expects even though the VCA response is linear.  Should I
be saying that different?

Larry (brain exponentially declining with age) Hendry