A-143-4

Module A-143-4 is a fourfold voltage controlled low frequency oscillator (LFO). As the frequency range includes moderate audio frequencies it can be used as a four-fold VCO too.

four independent VCLFOs/VCOs with triangle core
frequency range switches: low (bottom position) = LFO mode, high (top position) = VCO mode
two frequency control CV inputs for each unit:
– CV1 without attenuator (~ 1V/oct)
– CV2 with attenuator
manual frequency control
internal jumpers for the frequency range of the manual frequency controls:
– jumper not installed: ~ +/- 1 octave range (mainly for VCO applications)
– jumper installed: ~ +/- 5 octaves range (mainly for VCLFO applications)

Sync inputs:
– combined Reset/Direction inputs for unit #1 – #3
– separate Reset and Direction inputs for unit #4 (normalled sockets, i.e. Reset is connected to Direction if the Direction socket is unused)
– up/both/down direction switch for unit #4, for technical details concerning the Reset and Direction function please refer to the sketch below
triangle and rectangle outputs for each unit
typ. output voltage range -5V … +5V for both outputs (i.e. about 10 Vpp, symmetrical with reference to 0 V)
red/yellow LED displays for the triangle outputs (red = negative output voltage, yellow = positive output voltage)
common control section with two CV inputs and manual control (these inputs and controls affect the frequency of all four units)
sum outputs for triangle and rectangle with red/yellow LED displays
optional ultra-low frequency mode: for this a negative voltage can be applied via a jumper internally to the CV2 input of each unit and the common section (i.e. a negative voltage is normalled to the socket CV2 in question). Then the CV2 attenuator control works as a negative frequeny control (i.e. turning up this control lowers the frequency). Herewith LFO periodes up to about one hour (or even more) are possible.
optional CV bus access via jumper (i.e. the module can pick up the CV from the A-100 bus, e.g. generated by a Midi/CV or USB/CV interface A-190-x or a bus access module A-185-1/2), if the jumper is installed the bus CV affects all four units as the bus CV is added to the CV generated by the common control section
typ. frequency range: < 0.001 Hz (~ one hour, LFO mode with ultra-low option) … 15 kHz (VCO mode with installed frequency range jumpers for the manual frequency controls)
heat-up time: ~ 15 minutes (required to heat-up the main circuit by theCa affixed oven)

Per unit: CV 1 (around. 1V/octave), CV2 with attenuator. Triangle and square outputs; combined reset/direction inuts for units 1-3 and a separate reset and direction jacks at unit 4.
Common control for LFO1-4: CV1 (around 1V per octave), CV2 with attenuator, mixed outputs for triangle and square waves.

Technical Specs.:

• Width: 22HP
• Depth: 60mm
• Current Draw: 100mA

http://www.doepfer.de/a1434.htm