MiK-one

Device type	Rack synthesizer
Purchased when	13-Feb-2006
Purchased where	DIY project
Price including S&H	TBD
Condition when purchased	DIY
Current condition	working
Status	in use

The design goal was to squeeze a modular synthesizer into a small box and make everything controllable via MIDI. So there are not just a lot of CVs in this unit but also many analog switches, as the "wiring" between the modules should be very flexible. Now what modules does it have?

• Dual VCO with all standard waveforms (sawtooth, inverted sawtooth, triangle, sine, pulse)
• One sub-oscillator for 4 octaves per VCO, all 4 outputs per sub oscillator can be individually switched on and off
• Ring modulator, implemented as a 4-quadrant multiplier around an AD633
• Noise source
• Dual 12dB state variable filter with resonance
• 27 VCAs for audio and modulation signal level control
• Routing between components established using 2 buses with 8 lines each, routing is controlled with lots of 4051 analog multiplexers
• Due to the limitation of the signal levels on the 4051s, the bus amplifiers clip the signal, so overdrive is possible with nearly every signal
• Envelopes and LFOs are implementable in software, they are fully programmable among other possibilities of the responsible "modulation processors", of which 32 exist
• Nothing is static. Like in a modular synthesizer, you can wire anything to anything else, and this also applies to the MIDI signals. You can also route analog signals to MIDI out, if you want to
• Auto-tuning of the whole system. There is not a single trimpot in this unit, the software makes sure everything is perfectly adjusted any time. The online calibration procedure kicks in after some seconds of idle, which is detected by no MIDI traffic coming in, no note playing and the main output volume CV is zero

The firmware is far from completion, the user interface is currently missing completely. The synth uses 64 CVs internally, which led to the PMVC project. Both projects use a very similar platform, so the user interface will be nearly the same on both units. Physically, only the PMVC currently has a user interface, but exactly the same one will be used on the MiK-one, it just has to be built. After this, the remaining functionality of the firmware can be implemented. The backend engine functionality is nearly complete, the synth is even usable in the current state.

This is my first DIY project i started after not working with electronics for about 15 years. It was some sort of educational project, i had to refresh my old knowledge and learn a lot of new stuff, as i never did much with analog electronics up to now. But i worked a lot with digital electronics and microcontrollers before i went to IT, so a lot of this also can be found in this synthesizer.

The main idea was to create a very special polyphonic monster analog synth for the market, but during development, the project grew to something which would be too expensive for the market and too complex for a polyphonic edition. So this is my freaky monophonic toy with a real lot of possibilities.

The content of the old server showing the development photos and sounds is migrated onto this site now. Look here for the videos and audio demos and here for the photos. All this will be included in this page soon, with the description of the development process. I took enough photos and audio demos to create the story of the development of this synthesizer.

By the way - i really had all about this synth in my head for around 2 years. I just had some notes about the VCO and VCF design on paper. I have done the real schematics after two years after stating this project. So in fact i had to reverse-engineer some of the modules a bit to get the last details, most of the synth was soldered together without any EDA help, just from my head. I can't recommend this workflow :)

Continue reading on the following pages, they will fill up with more information with the time.

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