Inside the Volca Bass

Had a solid hour of fun with the Bass before I popped it open. 

I was hoping to add a MIDI jack to get MIDI out since it is clearly labeled:
I couldn't find space in the case to place a DIN jack so I am going to order a couple stereo 1/8" jacks to break out the MIDI that way.

I didn't do anything too crazy; just broke out the marked test points on the PCB

The jacks fit perfectly

Interesting that the SMD LEDs are on the other side of the PCB and they shine through holes

Used the ground point from the battery

Left an extra hole for the MIDI

 The jacks let me patch into both waveforms from all 3 oscillators, and the raw signal out of the VCO, VCF, and VCA.


  1. Hi,

    what is the VCO test point. Is it a pitch output? CV for the VCO programmed?

  2. Have you tested the 'Reset' pad? Would that be a VCO sync in?

  3. I think the VCO output is the oscillator pre VCF and VCA.

    im curious to know what the sync test point's function is.

  4. some ideas for uses of these outputs?
    apart from sending to a modular, etc.
    would yu re-route them back in, with
    a patch point to somewhere?
    been wondering if oscillator sync could
    be done - and other mods. Blackout did
    an individual level control for each osc,
    but it seemed complicated and is not
    really documented.

  5. On the Volca Keys (I don't have the Bass), the test points are all outputs - I checked with a small amp.

    SAW1-3 & SQR1-3 - ungated raw waveforms. They do their own thing between notes, so not very useful unless you gate them. There's an arpeggio played every few seconds, if you don't press a key - presumably to do with auto tune.

    VCO Out - gated combined waveform, chosen by the Voice knob. It starts when the note starts, and ends at the end of the release phase of the envelope.

    VCF Out - post filter signal... affected by the LFO, I guess. I forgot to check. The official block diagram says it is.

    VCA Out - cleaner pre-delay line out signal, with envelope (everything but the delay stage affects it)