Testing your build

Initial power on

Before diving in to using your new synthesizer let’s ensure everything is working and tuned properly. Screw in standoffs to the filter board then attach the filter board to the control board via the 8 pin headers on the left side of each board. Once everything is sandwiched together plug in a 9-12V DC power supply. The LCD and LED’s 3 and 7 should light up. Click around the buttons to switch through menus and ensure each LED lights up when it’s corresponding button is pressed.

NOTE: If the LCD is lit but you do not see any characters adjust screw trim pots on the bottom of the control board until you see text. This may require detaching the two boards from one another.

At this point you should familiarize yourself with the manual for this synth to understand the basic operations of how to interact with it. The full manual can be found here - https://mutable-instruments.net/archive/shruthi/build/digital_xt/


To tune the synth you will need to dial in the following settings.

  • Oscillator 1 shape: none
  • Oscillator 2 shape: none
  • Filter cutoff: 64
  • Filter resonance: 63 (maximum value)
  • Filter envelope and LFO modulations: 0

You’ll need a MIDI source to test this - preferably a keyboard. When playing notes you should hear a pure tone (sine wave), which does not come from the Datadealer's oscillators but from the filter self-oscillating. Adjust the V/Oct trimmer with a flathead screwdriver so that intervals are respected between octaves. Playing C3 won’t necessarily play a C but C3 and C4 should be one octave apart. If you have trouble tuning by ear you can try a tuner built in to a DAW such as Ableton. If the filter is correctly tuned, you should be able to play the filter “self oscillation tone” across roughly 4 octaves with correct tuning.

If you're having trouble please visit the troubleshooting sections of http://mutable-instruments.net/shruthi1/build/smr4mkII and http://mutable-instruments.net/shruthi1/build/digital for solutions to common issues. If you’re having no luck after that please send a detailed email to [email protected]

This guide was first published on Oct 12, 2016. It was last updated on Oct 12, 2016.
This page (Testing your build) was last updated on Aug 08, 2020.