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, 

- triangle and rectangle outputs for each unit 

- 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 internal jumpers that define which outputs are summed) 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: ~ 10 minutes (required to heat-up the main circuit by the affixed oven)

technical details

Width: 22HP 

Connections unit A-D: 
CV1 input 
CV2 input 
Square output 
Triangle output 
Res./Dir.-input (A-C) 
Reset input (D) 
Direction input (D) 

Common CV1 input 
Common CV2 input 
Square Sum output 
Triangle Sum output