Shruthi-1 Build

Hi all !

I’m finally gonna start to build my SMR4 mk2 after doing some other kits to practice. This one is the standard kit but I ordered it with the red plexiglass case, simply because I couldn’t resist to achieve the Polivoks style. However, I completely forgot the colour scheme for the lcd and leds on the kit.

I was wondering if I can order any other red on black lcd/oled and also red leds and just implement them in the build, or if I might have to order some other parts that are not included in the vanilla kit for them to work properly ?

Thanks guys

If you order the right type you should be OK.
There is one resistor that is matched for the leds in the LCD so you might have to change that. But Oled doesn’t need the resistor.

So, if I order this red on black LCD, can I follow the kit instructions step by step like it was the default LCD ?

Also, can I also get some red leds and follow the instructions for the kit ?

I’m still learning about this whole thing and I guess moving outside the instructions could result in more harm than good, therefore the worry about having to make changes just to be able to customise my shruthi.

Regarding the Ambika, I also have one of the kits that were sold this month. I think I’m gonna leave the leds as they come but would be interested in getting one of these screens. Can’t seem to find them at mouser does anyone know what they are precisely ?
Edit: similar to the midnight edition shruthi screen colour


Yes display and led look fine… You don’t have to use a resistor for the display. You can just use a piece of wire.

Alright appreciate shiftr !

I know this should be on ambika forum but can someone also point me out to a compatible blue LCD for it ? One that doesn’t require a transistor cause I’ll be doing it from a kit !

Hi guys !

I didn’t solder the MIDI socket correctly so now it’s not sitting perfectly on the PCB… I wonder what can happen later on in the build ?

Although I can use the braid to take the solder out of the back of PCB, I can’t manage to get the solder out of the front, making it impossible to push it to it’s place.

Any suggestions would be appreciated :wink:

I decided to continue… after soldering the other MIDI socket they are not that different, just a little.

Maybe someone can help me out with this.

Everything is done except the LCD. I’ve tested it and it’s working as expected, I can send midi notes and it plays, parameters change and every led is ok.

After testing it I remembered that I still had to cut every joint at the LCD area because I decided to leave it for the end.

After trimming them, to be able to get sound when I play it, I have to slightly press the Control Board against the Filter Board on the right side - if I press the encoder for example I get sound, if I press the preset button I also get sound…

Does anyone know what this is ?


I think I’m just too concerned with everything, as usual. Tightening the spacer at the right makes it behave normally

Guys, is it normal that my filter is self-oscillating already without tuning at the same note through octaves ?

And why is the filter playing accurate keyboard notes except that C is a B ? everything else matches the keyboard…

I guess it came already tuned… I have 7 octaves of C’s being B’s starting from the top, when I reach the 8th low octave it starts drifting by a semitone…

Calibrating the filter means not that you calibrate it to play the notes correctly - it means that the voltage differences between the octaves is matching. So this behaviour is not an issue, as long as an octave triggered on the keyboard is corresponding to the note played.

Thank you nightworxx ! it came calibrated already…7 octaves and then drifts only by a semitone.

That’s a very good outcome…

Is it normal that the output of the SMR4 is lower than the 4PM ? same input gain on the same interface gives me different results…

I noticed I was having some noise on the audio out socket when I moved it… also I started having some white noise whenever I pressed any of the buttons.

I opened it to find that I only solder 1 leg of the 2/4 pole connection, how dumb…

At the moment it’s working fine again, was just curious about the output ?

Gonna put it in the case again and check if the button noise comes back.

Cheers guys

Yes, differences in signal level are normal.

Thank you !