The MOTM-700 is another Synthesis Technology
exclusive module! It is a bi-directional, dual SPDT switch
that is "toggled" when an input control voltage exceeds a trip-point
set by a panel knob. Special circuitry handles routing of audio
(cross-fading VCAs) or control voltage (fast, low-offset switches).
The MOTM-700 has 2 identical sections, so we will discuss how one
of them operates. The two are totally independent from each other,
and by patchcords can be connected in series or parallel with each
other, or to additional MOTM-700 modules.
Think of a SPDT (single-pole, double-throw) mechanical switch.
When the switch is 'up', Signal A is connected to the "Common"
terminal (let's call it 'X'). So we say, "A is routed to X". If the
switch is 'down', then Signal B is connected to X. There are 2 ways
of veiwing the connections: 2 inputs are selected to 1 output, OR 1
input is routed to 2 outputs. The switch doesn't care: it's truly
bi-directional.
This is exactly how the MOTM-700 works! What makes it useful in
any studio is that you control the selection with a
control voltage! The MOTM-700 uses a circuit called a comparator
that "compares" the input control voltage with another voltage, set
by the panel pot SWITCH. The SWITCH control is adjustable from -5V
to +5V.
Operation is easy to remember:
- If the CV IN voltage is less than the SWITCH setting,
then A and X are connected.
- If the CV IN voltage is greater than the SWITCH
setting, then B and X are connected.
So, what is it good for? The fun part is choosing the source of
the CV input. Here are just a few examples:
- Use a voltage-out footpedal. Pedal up, A routes to X. Pedal
down, B routes to X.
- Use an LFO waveform. A triangle will cause the A and B signals
to "ping-pong" to X. Then the SWITCH setting determines the
duty-cycle of the routing!
- Use the S&H output from a MOTM-101. The SWITCH setting
becomes a voltage-controlled probability function! The higher you
set the voltage, the greater the chance A routes to X.
- Use the output from your keyboard controller. Instant
voltage-controlled splitpoint control!
A MODE switch selects if audio or control voltages are being
routed. In the AUDIO position, a special IC actually switches by a
very fast cross-fading between channels. This eliminates "pops" and
"clicks". The IC is rated for CD quality switching: better than 90dB
SNR with less than 0.002% THD. Shielded RG-174 cables are used for
all audio signals.
If the MODE is voltage, then a high-speed, low resistance CMOS
switch is used (NOT the cheesy '4066' types!) This IC is good enough
for switching VCO control voltages without adding drift or offsets!
It can also switch at audio rates as well! This can
result in some very bizarre timbres. Check out the demo files!
We think that the MOTM-700, once understood, will find 100's of
uses in your studio. Not just as another module in the MOTM family,
but as a 'stand-alone' accessory for routing just about any signal
in your setup.
;)
