The Boss MT-2 Metal Zone distortion pedal is one of the most complex drive pedals there is, and has probably the most sophisticated (and least understood!) tone control circuit on any mass-market pedal. It’s also quite a divisive beast, with some loving it, and others hating it. It’s a great pedal for modifications – easily available, […]
Author: Tom Wiltshire
What’s a “compander”? It’s a simple way to make your circuit quieter! So how does it work? Let’s say we’ve got a fairly noisy effect, like a BBD. The basic idea is that you make quiet signals louder before you put them through the effect, and then you make them quiet again after the effect, […]
How do you synchronise your modular synth with MIDI equipment? MIDI provides the MIDI clock message, but you need something to convert this to a format an analog modular synth can understand. Most MIDI-to-CV convertors will do the job, but that can be expensive. Here’s a cheap way to do it. The Druid MIDICLK chip […]
I typically use the 12-bit MCP4822 DAC to produce a CV for the SSM2164 (or CoolAudio V2164, it’s the same thing) . This is a good, cheap combination. However, the 4822 produces an output of 0-4.095V, whereas the 2164 needs 0-3.3V. It is possible to use a simple voltage divider to reduce the voltage to […]
I’ve been curious about Chorus for a while, since I’ve been working on and off with chorus design myself. There were a few things I didn’t understand, like what the relationshp is between the modulation LFO’s waveshape and the frequency modulation of signals going through the chorus. You’d think that if you use a sinewave […]
Years ago, I discovered that it was possible to analyze a waveform and discover what harmonic components it was composed of, and that the magical technique to do this was called “Fourier Analysis”. I tried to find out all I could, but all the references I could find were aimed at university level mathematicians, and […]
The PT2399 datasheet gives some data showing the relationship between the resistor on pin 6, the clock frequency, and the delay time. Unfortunately, it doesn’t offer any design equations relating these three variables. So, can we derive some? Yes, we can! They’re all included here. First, a quick summary of what I’ve learned, if you […]
There are a number of situations where it is useful to be able to crossfade between two different signals with a single control. Examples might be a wet/dry control on a delay effect, or a waveform knob on an oscillator that goes from ramp to square continuously. The simple and obvious way to do this […]
This project is a development of my earlier VCADSR envelope generator. Whilst that chip had both GATE and TRIGGER inputs, this chip replaces the TRIGGER input with a MODE CV that allows selection of normal ADSR, Gated looping, or full LFO-style Looping modes. Standard ADSR mode generates the shape you expect, and allows CV control […]
A single chip 1V/Oct voltage controlled digital oscillator, with 20 waveforms in a scannable wavetable. The VCDO uses a PIC 16F1847 microprocessor to create a versatile and simple voltage-controlled 8-bit digital wavetable oscillator. All oscillator parameters are controlled by 0-5V control voltages. The chip has a native exponential control response, making interfacing with 1V/Oct control […]