StringTheory Synth Owner’s Manual

StringTheory is a lo-fi, 4-note, paraphonic string synthesizer, based on the Solina String Synth emulation designed and coded by Jan Ostman.

Connecting StringTheory to your system


Power comes from a 2.5mm x 5.5mm DC jack socket, centre-positive, which will accept power from any “wall-wart”-type supply capable of delivering between 9 and 12V DC, to a maximum of 1 amp.


StringTheory relies on a MIDI connection. The front panel DIN connector accepts a standard MIDI cable. The MIDI THRU connector will pass through all MIDI signals, allowing you to place StringTheory in a “chain” of MIDI devices.


The gate out socket will send a voltage of approximately 5V while StringTheory is receiving a MIDI note. This can be connected to the gate input of other devices, such as other synths or Modular synth modules.

The gate LED will light while a gate signal is present at the output.


The out socket sends audio to an amplifier, other synth or to a mixer device.



The envelope knob controls a combined A-R (Attack-Release) envelope for the synthesizer. At the 12 o’clock position (marked “0” on the panel) the Attack and Release will both be set to zero, resulting in an on-off sound. Turning the knob clockwise will increase the Release time whilst maintain a short Attack. Turning the knob counter-clockwise will increase both the Attack and Release times.


This knob controls the string “ensemble” effect. At the zero position, the effect is off. As the knob is moved clockwise, a phaser-like effect is applied to the sound, thickening and widening it.


This knob applies a leslie-like lfo modulation/detune to the sound. At the zero position the effect is off. Turning the knob clockwise switches the effect on and increases its frequency.

MIDI Learn

Above the Gate LED is a small hole in the panel. A paperclip or wire can be inserted into this hole and used to press the switch located beneath it; doing so puts the device into “MIDI Learn” mode. When the device is in this mode, the gate out LED will flash continuously.

When in learn mode, the device will listen on all MIDI channels for a MIDI note message. When it receives a note message, it will set the device to listen on that MIDI channel only. This setting is saved to StringTheory’s internal memory so that the channel setting will be preserved even when powered off/on again.

After the channel and reference note is set, StringTheory will wait for a second note to set the MIDI offset. This allows you to transpose the output from StringTheory – commonly, this is used to offset the module by one or more octaves.

So, for example, if you pressed note C2 to set the MIDI channel and reference, then pressed C4 to set the offset, note C2 will sound whenever you play C4 – this offset of 2 octaves will also be applied to all other notes.

If you don’t want to set an offset, simply press the same note again.