The DRM2 core can be seen as a sound section (Osc,Filter,Amp) and an associated
control section (Trig, Envs, S/H). The block diagram shows the circuit blocks that make
up the DRM2, their associated controls and I/O, and the signal flow. Note the use of
colours to denote function and the use of
Int
for internal signal routing vs.
Ext
for external
control inputs.
Sound Section
Oscillator:
The Voltage Controlled Oscillator (VCO/Osc) is the core sound generator, but
it can also function as a modulation source at audio or low frequencies. It is a triangle
core design with temperature compensated exponential control (1V/Oct), the frequency of
which is governed by a summation of the Tune/Fine controls and any of the modulation
inputs.
•
The output is sweepable from Triangle to Square with the Shape control and its
output (+/-5V) is provided at the green Osc socket.
•
The Tune control sweeps the frequency over the range of approximately 1Hz to
10kHz, while the Fine control gives a 1 Octave range. The Osc can go well beyond
these ranges with CV control.
•
There are two Internal modulation sources – Bend from the Bend Envelope and Int
Mod which is switchable between S/H or Noise modulation (with centre off)
•
There are two External modulation sources – a precision 1V/Oct input for pitch CV
(accurate over about 6 octaves) and Ext Mod with switchable polarity. Each input is
designed for typical 10V peak-to-peak signals but accepts anything up to +/-15V.
•
The Oscillator can be synced (reset) on each Trigger Event via an internal jumper
(set ON as supplied). This resets the Triangle wave to 0V.
