Doepfer A-100(~ 40 MB) - Manual (Page 597)

doepfer
System A - 100 Dual Voltage Inverter A-175
5
Fig. 2: Mirroring a series of notes
AM with control of timbre
The example in Fig. 3 shows amplitude modulation
with timbre control.
The frequencies of both the carrier VCO (VCO 1) and
the modulator VCO (VCO 2) are in the audio range.
The pitch CV from the keyboard is patched via an
A-175, and so is inverted before it controls the modula-
tion amount (VCA 2). The result is that the sideband
harmonic distortion is stronger, the lower down the
keyboard you go (see also the user examples in the
A-130/1 manual).
Fig. 3: AM with timbre control
P As an alternative, a free-running VCO 2 can
be used to supply the pitch CV.
You can expand this patch by adding an
A-120 VCF after VCA 1, and controlling its
cut-off frequency with the inverted pitch vol-
tage. This has the effect of filtering out more
of the sidebands in higher notes.
CV
VCO 1
VCO 2 A-175
CV 1
CV
A-175
VCA 2
VCO 1
VCO 2
Gain > 0
VCA 1