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Standard Edition
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Vintage Edition
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Module A-111-3 is an extremely space-saving
precision VCO/LFO with a 4HP panel
only. Essentially it's the same basic circuit as the A-111-2 but with reduced
features:
- triangle core
- fully analog design
- min. 15 octaves pitch range in each mode
(VCO/LFO):
- VCO mode: typ. 0.5 Hz - 20 kHz (with appropriate external
CV)
- LFO mode: typ. 0.001 Hz -
40 Hz (with appropriate external CV)
- range switch so that the
module can be used as VCO or LFO (in LFO mode all frequencies about 1/500
compared to VCO mode)
- about 24 octaves total in both modes (typ.
0.001 Hz - 20kHz)
- perfect 1V/octave tracking over min. 10
octaves (typ. 16Hz - 16kHz in VCO mode)
- exponential frequency section:
- Tune control
- selectable tune control range by means of
an internal jumper: about 0.5 / 2 / 10 octaves
- manual VCO tune range (with jumper
pos. 1, without external CV): about 16 Hz- 20kHz
- manual VCO tune range (with jumper
pos. 2, without external CV): about 16 Hz- 70Hz
- manual VCO tune range (without jumper,
without external CV): about 16 Hz- 22Hz
- if desired the min. frequency can be
adjusted by the user (frequency offset trimming potentiometer, see
note below)
- the corresponding
frequencies in LFO mode are about 1/500 lower, the max. frequency in
LFO mode is about 40Hz
- 1V/octave CV input "1V"
- exponential frequency modulation XM input with attenuator
- the XM input socket is normalled to a
small positive voltage so that the XM control works as fine tune control
when exponential FM is not in use. As a logarithmic potentiometer for
finer resolution in the lower range is used, also the fine control is
exponential
(thank's to Václav of Bastl Instruments for this tip at
Superbooth in Berlin)
- access to internal bus CV (via jumper,
optional, please remove the bus jumper if this feature is not used to
avoid unwanted frequency modulation as then the unused CV line of the
bus works as a kind of antenna)
- linear frequency section:
- linear frequency modulation input LM
(without attenuator), DC coupled
- Pulsewidth section for rectangle output:
- Manual pulsewidth control PW,
adjusts pulsewidth from 0% (output = fixed at "low" state) up to 100%
(output fixed at
"high" state)
- Pulsewidth modulation input PM (without attenuator), about 5Vpp
required for full PW range
- Sync input SY (selectable hard or soft sync via
internal jumper, CEM3340
hard sync type)
- Waveform outputs:
- Nearly "perfect" waveforms
- LED (for display in LFO mode)
- only 4HP panel
A-111-3 is also the ideal companion for the
subharmonic generator A-113.
The following document shows the
positions and functions of the jumpers and trimming potentiometers of the
module: A111_3_trimming_potentiometers_and_jumpers.pdf
Technical remarks:
-
The control voltage applied to the socket 1V/Oct is added to the control voltage
coming from the bus (interruptible by removing the jumper JP2). Connecting a
cable to the socket 1V/Oct does not interrupt the bus CV connection ! I.e. the
1V/Oct socket is not normalled to the bus CV. This allows
e.g. transposing sequence CV (applied to the socket 1V/Oct) by the bus CV
(e.g. connected to the CV output of a Midi-to-CV interface).
-
The module is based on the CEM3340 circuit. The hard sync of the CEM3340 works
different compared to most other VCOs. The excerpt from the data sheet shows the
details:

The
CEM3340 type of hard sync is also explained in the A-111-1 user manual on page
9: A111_man.pdf.
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