Archive of the former Yahoo!Groups mailing list: MOTM

OK, I'm gonna step up to the plate on this because it has been something I
have been thinking about for a while. I'll say what I think a good panner
fader should do. Then, I will offer a very inexpensive solution in my mind
that can also be a useful utility module when not in use as a panner fader:

What should a panner fader do:
- Use a single input signal
- Allow each control to be annenuated for desired effect and vaioed input
out requirements.
- Allow each control to be biased to contol the amount of signal overlap, or
lack there of in the pan / fade
- Support different response curves.
- not add a lot of real estate for specialized VCAs.

So, while Paul's does plan a MOTM-130, which I will own, I have another
suggestion. Instead of creating a VCA fader panner, create a fader panner
control voltage module. This single 1U wide module would work with your
external control signal and not act as a VCA, but instead process the
control signals into the format desireable to control your already existing
quaility VCAs.

Unless I am overlooking something completely obvious, the processing of the
CV signal is no more than how much gain and how much offset. And, if you
use a single input, you want an internal inverter for the second CV
processing.

So, the module looks like this: 4 knobs and 4 jacks. It is a CV processing
module. The 4 controls are offset A, gain A, offset B, gain B. I'd probably
make all 4 controls reversing. The gain of each is 2.0 so you have the
flexibility to take 5 volt signals to a full 10 volt swing or attenuate a 10
volt signal to 5 V. The offset is probably +/-5 volts. 2 of the 4 jacks
are the 2 CV ouputs that go to our VCAs. One input jack is required. for A
and B.

A forth jack could very easily be the B channel input normalled from A so
that for panning and fading, only one input source is required. Or, a forth
jack could be an output that was equal to A+B. In this case a 3rd voltage
is generated that represents a voltage that could be used "fill in the gap"
between two faded signals or just the opposite.

The advantage of the B input jack is that this module is now a neat little 2
channel CV processor that can be used anytime you want to bias or attenuate
or apply some gain to a CV in a 2-in, 2-out format. The advantage of the
A+B output is a unique 3rd CV so that a 3rd VCA can be entered into the
equation in some creative fashion. Real estate does not support 5 jacks.

So, that is my 2 cents on the subject. This would be a simple module to
construct. Essentially if is a handfull of op amps wired up in the correct
configuration. You put one of these next to a MOTM-190 and you have panning
fading with maximum control in only 2U. And, you get to take advanage of
VCAs you already own,

Larry H (seeing a Stooge panel run for a simple CV DIY processor module).