Quattro Figaro

Quad VCA with CV Invertors and Mixed Outputs


Quattro Figaro is a 4 channel VCA (voltage controlled amplifier) with one CV inverter per channel and outputs of mixed channels. Each channel A, B, C, and D has its GAIN knob, CV IN jack with ATTENUATOR knob, INVERTED CV OUT, SIGNAL IN, and SIGNAL OUT jacks. The signal gets amplified with gain linear to the control voltage. Control voltages above 6 volts get compressed non-linearly (property of VCA chip). The maximum gain is a little above 2. An amplified signal is outputted from the SIG OUT jack.

Internal routing

Internal routing enables you to use the Quattro Figaro as a simple and powerful panning /crossfading tool. Two pairs (A+B and C+D) are internally routed via the jack switches, enabling you to quickly set up the panning situation. Because the internal routing is done via the connector switches, you can use all the channels independently by plugging in the cables, which disconnects the internal routing.

The signal from channel A is routed to the switch on the signal jack of channel B (the same with C and D), which means that the signal from channel A is connected to channel B as long as there is no jack plugged into the signal jack of channel B.

INVERTED CV OUT of channel A is also connected to the switch on the CV IN of channel B (the same with C and D), which means that the inverted CV is connected to the CV input of signal B as long as there is no jack plugged into the signal jack of channel B.

Mixed outputs

The mixed outputs enable you to use Quattro Figaro as voltage controlled mixer or stereo panning voltage controlled mixer. There are outputs of signal A mixed with signal C, signal B mixed with signal D (note that these two outputs are inverted), all signals mixed together, and all signals mixed together but inverted.


  • 4 channel VCA
  • CV attenuator per channel
  • Gain knob per channel
  • each CV input has inverted CV output
  • mixed outputs -(A+C), -(B+D), A+B+C+D, -(A+B+C+D)
  • internally routed CVs and signals via connector switches (for easy panning /crossfading setup)
  • handmade locally by Bastl Instruments in Brno, Czech Republic
  • front panel from aluminium or oak wood with handmade custom knobs

Technical details

  • 10 HP
  • 35mm deep (skiff friendly)
  • current +12 < 40 mA , -12 < 35 mA
  • PTC fuse and diode protected 16 pin power connector
  • pdf user manual download

DIY kit

You can build your own Quattro Figaro with our DIY kit. Go through the complete assembly guide below and make sure that you understand all the steps.