Yet another sample and hold

This is a Kosmo format version of René Schmitz’s YASH sample and hold. Sample and hold is something used in a lot of contexts other than / more commercially important than synthesis, so there’s such a thing as sample and hold ICs that are readily available. This uses the LF398 chip. All Schmitz’s circuit does […]

CGS (Ken Stone) Active Real Ring Modulator

This is a ring modulator in Kosmo format. No, really. A real ring modulator. There are lots of “ring modulators” out there that are in fact no such thing. They have similar behavior, and may arguably be better in some ways, but they’re more properly called four quadrant multipliers or balanced modulators or something, whereas […]

ARP 2600 (-based) envelope follower

This is an envelope follower (EF) module in Kosmo format with mic and instrument preamplifiers. I looked, in simulations and on the breadboard, at several envelope follower designs (you can read about some of that by following the envelope follower tag) and ended up deciding to go with a design based on the ARP 2600 […]

How to vactrol

Look around the synth DIY world and before long you’re likely to find a circuit containing something like this: This is an attempt to give voltage control to a circuit, using a vactrol. A vactrol is a light source (classically a little neon or incandescant light, but these days an LED) and a photoresistor butted […]

Video: March of the Modules of March

IR Input

I’ve built my modification of the Barton Infrared Input. It’s pretty much as I breadboarded it with a couple of trivial exceptions. One is that I wanted to change the direction of the gate sensitivity/threshold pot… but I managed only to mirror it along with its inputs in the schematic, so it came out the […]

ATTENUɅƎɹꞱƎɹS

This is a Kosmo format attenuverters module. Not much to say beyond that! There are three attenuverters. One has a switch to select 10 V input instead of the input jack. There are jacks for output of the sum and inverted sum of the three channels. Response to slider position is nonlinear, giving you finer […]

Gerbers video

Here’s a walkthrough of the process of getting Gerber files (and the rest of a GitHub repo) off the web and uploading them for fabrication:

All in a week’s work

I built two modules this week: I haven’t installed these in the case yet, but when I do, that will be Kosmodrome Phase I complete. The envelope generator is a duplicate of the Kassutronics Precision ADSR I made previously. The VCO is a new design, part of a larger project which I’ll write up when […]

Playing with fire

The Barton BMC78 Infrared Input is one of those modules that realistically you probably would not use much, but it’s fun enough to want to build it anyway. It’s just an infrared phototransistor, AC or DC coupled to a buffer, with a CV to gate function. Check out the demo. I built the circuit on […]