This synthesizer arose from my wanting to make a portable modular that I could bring on the road or travel with to make sounds.  I decided on using two of Ray Wilson's Experimenter PCBs, his wall wart power supply PCB as well as Sample and Hold PCB.  There are also 2 4040 dividers I built on perf board, 2 CV distributors, an external signal input (for guitars or keyboards etc..) and one voltage controlled delay.  This left me with a very large sound making and modulating instrument that was light weight and portable.  Its a bit more fragile than I had hoped due to the case itself, but it makes some pretty intense sounds regardless. The banana jack color scheme differed on this project as well.  Red jacks are audio and control outputs, blue jacks are CV inputs, and black jacks are audio inputs.

Whats inside:

4 Voltage Controlled Oscillators 

4 Voltage Controlled Filters

4 Voltage Controlled Amplifiers

4 Low Frequency Oscillators

4 Attack/Release Envelope Generators 


Sample + Hold

Audio mixer

CV mixer

Voltage Controlled Echo/Delay

2 DIviders

2 CV Distributors

1 Inverter

2 Passive Attenuators

2 Banana to 1/4" adapters

This project took about 3 weeks of straight work, long hours and the wiring was intense.  The known issues I encountered: The mixer runs a bit hot, something I will eventually fix, there were some printing errors for the laminated graphics like CV and inputs being mislabeled on the VCAs.  The filters could benefit from sockets on the transistors to allow testing them out in the circuit.  As a nature of the simple circuitry the Envelope Generators only trigger from the full supply voltage, so I had to modify one of the LFO outputs to be a 12 volt pulse to trigger the EG's.  Other than all that its a pretty versatile sounding synthesizer.  

Here are the boards populated.

The beginning of the hole cutting phase..

flying wires!

I tried to stay organized..