MIDI in trouble [basically solved]

Hi, all. First, thanks for the valuable threads here that have already solved some of the issues I have had with my Шрути-1. But I remain rather stumped by my MIDI in troubles, and I haven’t found a thread that matches my issues.

MIDI out works–I did the backup/SysEx dump to my interface (NI Audio Kontrol 1) and the MIDI IN LED on the interface flipped out.

For the MIDI keyboard, I’m using a Korg microKONTROL, plugged into the wall (when plugged into USB, its MIDI out works exclusively as a MIDI-USB bridge). I don’t have easy acces to another device w/ MIDI out (except the Audio Kontrol 1, but I’m not sure if it can send MIDI signals out! I could get it to behave like a MIDI keyboard in my DAW, but that was via NI’s software). So here’s one potential stumbling point.

On the control board, the 6N137 behaves like this:

Pin 2 gets 0v but is connected to D1 and R19, through to MIDI in’s pin 4
Pin 3 gets 0v but is connected to D1 and MIDI in’s pin 5
Pin 5 gets 0v and goes to GND
Pin 6 gets 4.89v and is connected to R14 and pin 14 on the ATMEGA. When I jiggle pitchbend on the Korg, the voltage drops to around 4.7v or so.
Pin 7 gets 4.85v
Pin 8 gets 4.87v and is connected to C1, a 220 resistor, and R14

In other words, it looks like it should all be working, as the optocoupler does react to MIDI signals. But I don’t get the little note icon on the LCD (or pitchbend or anything else; I’m not even sure I know what they look like!), and, rather obviously, I get no audio out (though I do via the S1 trigger). I did these tests with the device on MIDI channel 0 and the Korg on channel 1, but even with the device on channel 1, I get no note icon.

Any ideas where to go from here?

They should both be on the same channel :slight_smile:
You need to play notes before the note icon appears and it usually dissapears rather quickly…

First, set Shruthis MIDI receive channel to 0 which is omni mode to rule out all possible Channel mismatching problems.

It is set on 0. I also tried it on 1, but I saved the default to 0.

Did you measure for continuity on all the connection you describe?

Yes, what I meant above when I wrote “connected” was that my multimeter beeps when I do continuity tests between the optocoupler and the other components.

Maybe try it with the NI to the midi in or with an other midi cable.

Do you get somethink like a soft synth working on your computer with the korg via a midi cable to the NI?

it’s not easy to say when you can’t be sure about your midi source. since everything else at leat looks fine, maybe just try to get hands on a midi keyboard to try. haha go to your local music store and say you need a midi keyboard but want to try if it works with your portable synth.
other than that, since you seem to need midi obviously, there’s good chances you can still grab a GM5 or GM5x5x5 board at midibox.org. those are reliable USB-MIDI interfaces almost for free (15-25€ overall material cost depending from 1x or 5x in/out)

If you need a gm5 chip and single pcb 1 I/O (though you can add 4 more I/Os with a proto board) PM me.

Thanks for the suggestions!

A breakthrough, and I finally see the note icon!

I created an “external midi” track in Logic, drew a pattern on the piano roll, and was able to send it to the Shruthi-1 via the NI, so:

Mac(Logic) -usb-> NI -midi -> Shruthi-1 (-audio-> amp)

works! Which means that:

Korg -usb-> Mac(Logic) -usb-> NI -midi -> Shruthi-1 (-audio-> amp)

also works! I can play the Shruthi-1 with the Korg. I only need two other devices in the chain, with one running costly software (I couldn’t get this setup to work in Live.)

This also works:

Korg -midi-> NI -usb-> Mac(Logic) (-audio-> amp)

to play a soft synth (I also couldn’t get it to work in Live), so it proves that MIDI out on the Korg works.

Yet Korg -midi-> Shruthi-1 (-audio-> amp) gives me nothing.

While searching this issue before posting, I saw that others had written that they had some keyboards that simply didn’t work with the Shruthi-1 for some reason. Maybe we should make a list of those keyboards and tentatively add the microKONTROL to it?

Needless to say, I think I can safely consider my Shruthi-1 FULLY FUNCTIONAL. Hooray!

I bought a microkontrol a few weeks ago… It works fine with my Ambika and anushri… Didn’t test it on a Shruthi yet but I don’t think it’s different…

Today I decided to see if this would work:

Mac(Logic) -usb-> Korg -midi-> Shruthi-1 (-audio-> amp)

and, well, it didn’t at first. Then I kicked the cable in disgust, and the synth sprung to life. So with the MIDI cable precariously bent and working, I shut both devices off, carefully removed the usb from the Korg, and, well…


Such a pleasure when the fix is so easy. The cable is literally brand new–I bought it only once the Shruthi-1 was complete, as a sort of present to myself for building a functional unit. Alas, it’s flaky, so I might just chop the heads off and resolder new ones on.

And that is the only way to cope with cables :wink:
Soldering them by one self saves money AND nerves…because time (for troubleshooting) is money, mostly not recognized - incognito !

Right. And it’s especially annoying since I had done continuity tests on the cable itself, etc., etc…

Yeah, but the problem with those mostly molded connectors is, that nobody could take a look inside. And so surprises are on the program, hehe…

Right. Anyway, everything is super functional, and I made use of the nerdy section of the manual to map the 8 encoders and 8 sliders of the microKONTROL to 16 diff parameters on the synth, and then I infuriated my neighbors.

Have no idea to what I should map the pads, other than maybe the trigger notes…