What pro artists use Mutable Instruments?


That’s pretty cool! Looks like there’s some kind of pressure/positional sensor on top:


^ Cool indeed!
I expect the mod is a soft pot. Likely linked to one of the CV inputs?


yes it looks like it’s a ribbon linked to the CV mod pads

I’ve recently seen a picture of Chapelier Fou for the promotion of his upcoming record, featuring a prominent Anushri in front of him.


^ wow that softpot mod is a really easy and smart mod for the shruthi!


Yeah, looks like it was soldered directly to the control board and just folded over the plexi.


@t2k It’s this softpot
It has sticky tape on the back so you can just stick it on the shruthi.


What’s it controlling? Pitch? Filter? Routable?


@shiftr, that is really cool! A bit expensive I suppose but really nice. Mouser, Digikey and Sparkfun have them too.


@Nedavine: In the Shruthi Mod Matrix, you can assign one of the 4 CVs to any parameter, so yes it is rout-able. To multiple parameter all at once! :slight_smile:

There are easy to mod points on the upper left part of the digital board for this purpose. I have considered adding a soft pot and a piezo to send triggers to make the Shruhi a portable drum synth.


@audiohoarder Thanks. I don’t have my Shruthi anymore and didn’t look into modding it when I did. I may build one again so this would be very interesting indeed.

The portable drum synth idea sounds great. If you do do it please share your results.


@Nedavine: It wouldn’t have been easy without the new Firmware allowing one to trigger the envelopes from a high value in the mod matrix. If they trigger from a 5V signal, it works. Simple as that. A cheap piezo is .50USD. Much cheaper than a soft pot.

I’ll have to wait to get a third Shruthi though. My first one is too personal to modify, and my second one is too cool with the aluminum panel. It will happen one day or another. Maybe I can just build these things into a case and sell that? Not a bad idea, haha.

Now, if I could make a 5V to 9V USB to barrel adapter, I could even use this nifty USB battery charger I got on sale to make it 100% portable. So far it is on track to power my BS2 for 12 hours straight. Not bad at all. I wonder if there is an outlet style version?


i’d be interested in the piezo mod. Where would you hook it up? Would it need more parts than just the piezo?


@Paulus: Ok. Get yourself a piezo with the wires attached, like this one.
I tend to get my piezos from disassembled drum toys. It is cheaper that way, but if you only need one, you can find them online with the wires for only .50USD or less. This one is a dollar.

If you get one without wires attached. Solder a black wire (ground) to the metal part of the disc, then solder a red wire (output signal voltage) to the ceramic disc.

First you will want to bread board and measure the signal strength. You do not want the signal to exceed 5V as these inputs are directly attached to the MCU.
Hook the black wire to your ground, and the red wire to the circuit you want to measure the strength of. You will want to put a resistor in parallel between the red and black wire. This value should be low, around 1 Mega Ohm. If you are exceeding 5V, change the resistor value until it is in the proper range.
Finally, put a protection diode in serial between the red wire and your measurement. You should not get negative voltages from a piezo, but I wouldn’t take any chances. You will get a voltage drop across the diode, so repeat the steps above. If it is in the neighborhood of 4.3 to 4.7 V, you are in good shape.

While you are doing these tests, see how sensitive the piezo is to lighter and harder taps. If you get constant voltage output, you will always be able to trigger an envelope from the Mod Matrix, but if the signal strength changes, you may be able to still trigger the envelope with a high mod amount value. However, you can also hook the voltage to velocity in the mod matrix if it is a sensitive piezo. Conveniently, you will only take up one CV input with this piezo.

Now that you have done the measurements, attach it to your Shruthi!

First, solder the red wire to your protection diode. Next, solder the ground wire to the GND and the protection diode to the CV in of your choice. Finally, solder the proper value resistor in parallel between the ground connection on the board and the CV input you soldered the protection diode to.

Now if that sounds messy to you, and I assure you it is, you may want to solder all of this together on a piece of pref board, then simply run two wires to the connections on the Shruthi digital board. That way there won’t be resistors and diodes in the way the next time you want to add a mod. :slight_smile:

You DO NOT need to solder this component to the 5V line. When you tap or other wise cause a piezo to vibrate it will generate its own voltage.


Thanks a lot for these very precise infos!
I’ll study it, except the perfboard, I think I have everything already. As soon as I have time I’ll get to it!


@Paulus: You’re welcome.
Just bread board it first if you don’t have a perf board.

As far as actually attaching the component. I was thinking about a case that has a soft pot built into the left side panel, and the piezo on the right side panel. This would allow for easy hand-held use. At least I think it would.
Let me know how you do attach it. I think I have a neat little idea to solve this issue, but I want to see if it is even necessary first.


Great idea for easy hand use. But I would more think of a separate mini box (extra thin for an example) so you could keep you Shruthi intact and have it like a controller for other Shruthis.
Well i’m dreaming now, work is crazy right now and I still have to order and build my LXR so I might take some times to get it done! But definitely one of my next project!


You can get a piezo from an old digital watch too. They used them for the alarm.


Moderat (Apparat+Modeselektor), studio picture (Braids).


That´s a cool shot


What’s on the shelf, looked like a Yamaha FB-01 but the logo is in the wrong place.