Making panels

Thought I’d write up something about my process for making front panels. Or rather for designing them — the actual making is someone else’s job. I’ve made my own in the past, drilling sheet aluminum and then affixing a paper overlay with a transparent plastic layer. But all the ones I’ve done in the past […]

Hole footprints

I’ve had 983 front panel designs fabbed in PCB material, FR4 (OK, 983 may be an exaggeration). Never a problem until my order in November when JLCPCB’s reviewer emailed: That was startling. The indicated holes are for 1/4″ jacks and are 10 mm diameter. They’d done plated through jack holes on every panel before this. […]

Turing to halting

The Turing Machine, designed by Tom Whitwell, is one of the most popular Music Thing modules. And like all the Music Thing modules it’s open source, so when Ben Rufenacht (of the LMNC Discourse group) decided he wanted a Kosmo format version, he copied the MT repo and laid out a Kosmo-size PCB and panel. […]

Pole mixing cancellation redux

Amazing what a good walk will do for your thought processes. I’d hardly set foot on the trail when I realized the pole mixing problem isn’t as serious a problem as I thought. The thing about the gains depending on the control voltage is they’re correlated. All four gains change about the same amount in […]

Pole mixing on the breadboard

Electric Druid shows a pair of partial designs for a pole mixing filter, one based on the V2164/AS2164 filter chip and one using the AS3320. I’ve been breadboarding a circuit based on the latter, and my results have… not been encouraging. There are a couple of errors in the Electric Druid schematics. There should be […]

Pole mixing

A while ago I mentioned pole mixing in a post about my all pass filter module. Pole mixing is a technique of combing the outputs of different poles in a filter with the input signal to get different kinds of frequency responses. For instance, suppose you have a simple 1-stage (or 1-pole) low pass filter. […]

Clock video

Calibrating and tuning a VCO

Let’s look at how to set up a VCO to track at 1 volt per octave (1 V/oct). This will apply to many VCO designs but I’m thinking particularly of 3340 based designs such as the LMNC 1222 Performance Oscillator or my Hero and Sidekick VCOs. The idea is to get the pitch to change […]

Processing voltages

There are sexy, unusual modules that can be very interesting. Then there’s utility modules. Not so interesting, but useful. Here’s one: The design for this started out as a clone of the voltage processor from the ARP 2600 synthesizer. There are two voltage summing sections and a lag circuit. One thing that always bugged me […]

Clocking in

I thought about building a clock module for Kosmodrome Phase 1, then decided I didn’t really need one at the time because Phase 1 had no modules that would need a clock. But now I’ve built the G.E.A.R. Sequencer and YASH. Clock needed for Phase 2! At one time my attitude was that it was […]