Advice on shruthi build troubleshooting [SOLVED]


I’m in the progress of assembling one (of the very last?) Shruthi midnight editions from MI (PCB’s only - self sourced components).

I’m at “Step 11: a first test!” after having assembled both controller board and filter board and have programmed the chips .

Playing the Shruthi in blind (there’s no LCD soldered yet) using a MIDI keyboard I’m hearing some quite distorted sounds. Attached is an audio snippet when playing while switching between the pages. The final one is with the LFO page active. You can hear the distortion pulsing with the LFO.


  • Does this seems familiar to anyone of you experienced builders?
  • Should I suspect controller or filter, IC’s or shorts?
  • I guess I need to resolve this issue before assembling LCD?

I understand that I need to provide photos of my crappy soldering to get help in that department.

Thanks for any help!

I would solder the display. Maybe you switched to XT mode without realising it and now your parameters are jumping around and that creates the weird sound?

The only thing that could fry the display is over voltage or a short. If the voltages are okay, why not mount the display?

Ahhh… Is this the kind of garbled/distorted sound you get if the default (SMR) filter board is selected for a SVF filter board?

This would surely explain it since I haven’t been able to select the SVF filter board without the LCD mounted.

I just don’t want to ruin the entire build by soldering the LCD too soon.


@TheSlowGrowth Thanks! I think there’s a 99.9% chance that you’re right. I get the same kind of weird sounds when selecting the wrong filter board on one of my other Shruthi’s.

Unless someone else jumps in and advice against it I’ll continue the build and solder the LCD.


Check the manual for how to switch filter modes, should be possible with just the buttons…

I’d post what I do, but I’m quite behind on firmware updates…

That’s a good idea - I’ll give it a go (boot, 1 press 5th button, 3 presses 4th button, turn 3rd pot)