Gear

I've built some stuff:

Kymatron

My homegrown analogue modular synthesizer.

2x VCO (saw, pulse, tri, sin, lin-FM and sync)
1x Dual State Variable VCF (SSM2164) selfoscillating, 1v/oct cv in)
1x Noise
1x Quad fourquadrant multiplier (MLT04)
1x Dual 4-bit counter
1x Dual 3-channel mixer
1x Quad 2-ch configurable bipolar mixer
1x Dual VC-switch + Dual S/H
1x Computer interface

Madmouse 1

A madmouse kit modified to semi-modular. This was a simple little synthesizer-kit that I built and modified from prepatched to a semimodular synthesizer.

2x Simple VCO with saw and pulse
1x LFO
1x Low-pass VCF
1x Dual A/D Envelopes
1x Slew limiter
2x VCA

Portatron

Portable semi-modular synthesizer. This was a simple little synthesizer kit (madmouse) that I built and modified from prepatched to a semimodular portable synthesizer, housed in an aluminium case.

2x Simple VCO with saw and pulse
1x LFO
1x Low-pass VCF
1x Dual A/D Envelopes
1x Slew limiter
2x VCA
1x Monitor with amplifier

Kymatica SDS-800

Modified Simmons SDS-800. Work in progress.. The sds-800 is a drumsynthesizer with four voices (bassdrum, snare, tom1, tom2). Each voice is based on a CEM3394 chip, which is a whole little analogue synthesizer in one chip. Each CEM3394 contains:

VCO with pulse, triangle and sawtooth.
4-pole low-pass VCF with voltage controlled resonance.
Voltage controlled mixer for adjusting the balance between the internally generated VCO waveforms and any external signal.
Modulation amount VCA for modulating the filter frequency by the triangle waveform output of the VCO.
Final VCA for allowing the output level be to voltage controlled.

But in the original sds-800, most of those features was left disabled and unused.

Trashofonium

Noise-machine I built for my friend on his birthday. The Trashofonium is a modified EQ with internal electric feedback, it also has sockets for connecting external gear into the feedback loop

CrackRadio

A cracklebox-like noise machine built of a radio. A small battery-driven AM radio can be a very interresting musical instrument after some circuit-bending... Simply find the best nodes on the circuit board and solder wires out to some touchpads made of screws fastened through a wooden plate.

CtrlBox

An USB control interface. This is a controller with 6 analog and 10 digital inputs, with an USB connection for controlling custom software on the computer. The analog inputs are 10 bit resolution, and connected to 4 knobs and 1 joystick. 8 of the digital inputs are connected to toggle switches, and the remaining 2 to push buttons. The serial protocol used resembles MIDI but is faster and higher resolution, 10 bits instead of 8. It's based on the Arduino microcontroller board with an AVR atmega168 processor. No batteries needed, it powers on USB.

CimbaTron

A 12-stringed instrument built from old guitar-parts.

Gate1

Manual gate with individual levels for on/off state.

PocketNoise

A small and simple noise generator.

EQ-2

The brother of Trashofonium, featuring feedback and momentary push buttons to cut specific frequency bands. Built for Martin Öhman in The Moth.

Kosmotron

small analog noise/drone synth in progress..

Schematics

(The PDF files were lost some year ago, will add them again some day...)

State Variable VCF

Based on CA3080. I never got the resonance to work as I want it.

Dual State Variable VCF

Based on SSM2164. Works much better than the CA3080 SVF!

Dual State Variable VCF and 1v/oct quadrature vco

Based on SSM2164. An enhancement of the filter above. This one features stable selfoscillating and 1v/oct cv-inputs. It doesn't go very high in frequency when oscillating, but is a very useful module anyhow…

Bipolar mixer V2

A very handy thing, each input has a scaleknob with "-/0/+" so it's easy to invert the signals. Each mixersections output is normalized to the next section, so that the sections link together to form as many mixers with as many inputs as you need… One channel on each section is normalized to a fixed voltage, so it can be used to add an offset voltage.

Quad fourquadrant multiplier

Built around MLT04 multiplier IC. This module may function as ringmodulators, VCA's, VC-crossfader, VC-panner, frequencydoubler (with sine input)

Voltage controlled switch

Built around MAX4533 electronic switch IC

Sample&Hold

Built around MAX4533 electronic switch IC. Very bad drooprate, maybe some better opamp-buffer and/or capacitor should do it…

Percussion Envelope

NOT TESTED. The idea is to have two alternative decay-times to choose between with logic input.

Computer Interface

This interface connects to the centronics parallell port and outputs 8 channel gate and 4 channel 1v/oct CV with 12 bit resolution. Based on MAX536 Quad ADC and 74LS244 Octal Buffer. I've redesigned this to use an Arduino over USB port instead, since todays computers does not have parallell ports..

Hardware