I finished up three modules recently:

(Left) Two Kosmo format synth modules, both 5 x 20 cm, white with black graphics. On the left, Nuclear Decay by TimMJN, with a knob labeled 'T_1/2' and a window behind which is a Geiger tube; there also is a radiation symbol, the text 'Caution: Air Shower Muons', and output jacks labeled 'Trig Out' and 'Env Out' (with a green LED). On the right, Bong0 by NLC, divided by a vertical line on each side of which are two knobs ('Env' and 'Freq'), a green LED, and three jacks ('In', 'Trig', and 'Out'). (Right) A third Kosmo format synth module, 2.5 x 20 cm, white with black graphics, labeled 'CVT' by 'AO' (Analog Output, which is me.) Has two jacks labeled 'IN' and 'OUT' and two toggle switches named the same; their positions are marked 0–10 V, 0–5 V, and ±5 V.

Nuclear Decay and Bong0

On the left is Nuclear Decay, which I’ve written up . All that’s new is the fabbed front panel — and the piece of clear acetate film I glued behind the window, to protect the Geiger tube and the user from one another.

In the middle is a dual Kosmo version of the NLC Bong0 drum module, the mostly-SMD project I wrote up recently too. It likewise was done a while ago except for the permanent faceplate, which it got today (along with some minor surgery to correct a backwards-wired pot). The original design is a simple twin-T drum in Eurorack format. I put two of the PCBs behind a Kosmo front panel. Making that work with decent knob spacing required a bit of sideways thinking, or rather upside down, which is how one of the PCBs ended up. Or down. If it’s good enough for SLIM it’s good enough for me.

Rear view of the dual Bong0 module, showing two PCBs — one upside down — mounted to the panel, with wires connecting to panel mounted components.

Bong0 behind the panel

On the right is CVT, my own design. A rather unsexy but useful little utility module. It converts signals from one voltage range to another. For example, suppose you want to modulate a VCA with a 0 to 5 V low frequency waveform, but your LFO puts out ±5 V signals. You can plug the LFO into IN, set the IN toggle switch to ±5 V, set the OUT toggle switch to 0–5 V, and patch OUT to the VCA. The waveform will be scaled and shifted into the desired voltage range. Signals in any of three ranges — 0–10 V, 0–5 V, or ±5 V — can be converted to any other one of the three (or to itself, for that matter).

The usual git repos:

<– 2024-02-19_dso138-oscilloscope-video — 2024-03-04_wave-displacer –>