Shruthi "CV" outs & Koma Field Kit

Hello guys,

So while I am waiting for my Field Kit from Koma to land in my studio, I am wondering how this piece of gear will fit into my setup.
I own no modular and therefore have no CV source to use with the Koma Field Kit. I do have a Boss DR-110 sending trigger pulses (5v I believe?).
SO, as I use two Shruthis as central gear in my setup, I was wondering if I could use the CV outs from one of them to controll different blocks on the Field kit? This way I could use the arpeggiator (or maybe send a clock signal?) as a modulation source and send it vhia CV1 and CV2 out or sync different elements of The Field kit with the rest of my gear (synced via midi).
I have no experience with CVs and never tried the mod on one of my Shruthi and I am aware that these are not exactly “CV”, but rather work as modulation input/output.

Thanks!

  • The signals will need filtering (at the very least a passive 4.7k / 47nF filter).
  • You’ll need to hack the enclosure of your Shruthi.
  • You’ll need to do this with a Shruthi whose filter board doesn’t make use of those CV (this won’t work for example with a dual SVF shruthi which uses those two outputs for cutoff2/resonance2).

Hey pichenettes, thanks a lot for these details.
Would you mind pointing me to a simple diy circuit for the passive filter?
Thanks!

@Paulus - maybe have a look at this thread? http://mutable-instruments.net/forum/discussion/6733/4pm-cv-in-for-cutoff-res-vca/p1

and this one: http://mutable-instruments.net/forum/discussion/7790/shruthi-1-vc-filter-box-kits/p1

I’m in a similar situation - mainly hoping to hook a shruthi up to the envelope follower on the Field Kit.

The circuits posted by elthorno are for something else - adding CV ins to the Shruthi.

The “circuit” I’m mentioning is just a passive RC filter:

“Input” goes to the Shruthi CV out; “Output” goes to the output jack.

Great! Thank you both! Really clear.
Can’t wait to try this!

@elthorno
it would be nice to have a thread here dedicated to the relationship between the Shruthi and the Field kit and to exchange discoveries or hacks.

@Paulus- may as well use the one here

@elthorno That’d be better indeed

Guys, I have these film capacitor around. Can I use these for the low pass filer?
Thanks

Yes.

Nice. Is it ok if the output is grounded (shield) without the jack plugged in (mechanically due to the jack socket) ?

It’s ok, the resistor will limit the amount of current dumped to ground by the PWM pin from the Shruthi but why can’t you wire things so that the output is left floating if the jack is not plugged in?

because I have these sockets on hand:


Can I solve it even better?

Oh, I just measured it, the tip is not grounded at all without the jack plugged in (between 1 and 2).

The PWM output is between 0V…5V for CV1 and CV2, right?

What the drawing of your part means is that if no jack is inserted in the socket, then the tip (5) and ring (2) will be connected to pin 3 and pin 4. But you don’t have to connect these pins to ground, you can leave pin 2, 3 and 4 floating.

thank you.

I read about optional CV scaling circuits in the old archives, but that’s not really necessary, is it?

Can you post a link to what you’re referring to?

https://web.archive.org/web/20170503135618/http://mutable-instruments.net/shruthi1/faq

…from the archive in faq:

„Does the shruthi have cv/gate Inputs/outputs?“