Thursday, March 17, 2011

Monotron-Squared Continues...

Got all the parts now, and all the boards are prepped. Just wiring up the pots and switches, and figuring out how to mount all the different parts in the enclosure. Also have to cut some traces and solder onto both monotron boards - mono 1 and mono 2 - in order to have dual VCO. May not be able to have SYNC option for the two oscillators, but will try anyways.
Also, using VCF 2 (filter of mono 2) as a stand alone filter, with its own line out.
Altogether will have dual VCO with in-built CV mixer to mix them, squarewave VCO waveshaper with PWM, a dedicated filter, and an audio out mixer to mix the mono 1&2 and the VCF 2 outputs.
To do all this, I utilized a voltage inverter to get +/- 5V supply voltages for the CV mixer circuit and the audio mixer circuit. The CV mixer was modelled from Din Sync's module(, with different Op-Amp and smaller supply, and the Audio mix out circuit was taken from the "simple mono mixer" at MFOS (
Anyway, still got tons of work to do - but should be done soon!

Here's the Square Wave & PWM board with all components installed. This circuit board includes a gated output.
Here's the votlage inverter and CV mixer circuits.
Same board as above, but with added Audio mixer circuit.

Board mounts for some switches and another board for the PWM pot, Square/Saw select switch, and polarizing switch for CV mixer; both were manufactured via chemical etching.

Where they'll sit in enclosure.
  Had alot of trouble trying to get matching knobs - so used regular potentiometers and knarled them myself!

Knarling me Knobs!

Looks more like monotron style knob.

Next to monotron knobs.

What they'll look like in the box.
Mounts for the filter knobs.
Mounts for the VCO mixing pots.
All the Op-Amps, and a spare 5532.

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