Dual Amplifier
The basis of the module is a pair of DC-coupled Voltage-
Controlled Amplifiers (or, more accurately, attenuators –
gain is variable from 0 to +1) each with a form of
waveshapping which can be switched in to follow each
VCA. The Initial controls sweep the VCAs from fully closed
to fully open.
The left-hand unit features a Linear response and two
Main Path inputs – one full scale (In A) and one with
attenuator (In B) allowing two inputs to be mixed.
The Fold switch brings in a 4-stage Wavefolder which folds
the waveform tips back in on themselves as amplitude is
increased [does not work with squarewaves!] resulting in
extra harmonics.
The Fold mode works fine with sub-audio signals and
folding kicks in around 9 o'clock on the Initial dial.
Try mixing a sub-audio signal into In B while running an
audio signal into In A for a width modulation effect.
A passable white-noise source can be made by patching the
Out to In A and turning the Initial dial up to near full.
The right-hand unit has only one Main Path input (again
DC-coupled), but the response can be swept between
Linear and Exponential which gives a sharper response from envelope modulation. It also features
a 2
nd
unattenuated modulation input.
The Sat(uration) switch brings in an amplification stage with zener limiting at +/-5V. Soft-clipping
begins to occur after around 9 o'clock on the Initial dial.
A 4 quadrant multiplier (Ring Modulator) can be patched using the two sections combined with the
DC Mixer.
•
Switch both to VCA mode with Initial control set to around mid point
•
Feed the same signal (carrier) to each side (In A and In)
•
Feed a bipolar signal (modulator) to the centre CV inputs (CV and CV A) but set them to
opposing modulation depths (one fully clockwise, one fully anti-clockwise)
•
Take the two Out signals to the DC Mixer and combine them with one inverted
•
Tweak the Initial dials to minimise carrier and modulator bleed-through
There are no internal adjustment parameters for this module.
