Nearing Completion!

So I finally got my digital board in the mail today and am almost done putting the last few pieces together! For those of you that haven’t seen my other thread, I built the CEM3379 board on perfboard a few weeks ago in anticipation of the shruthi release, and installed it in a classy looking cigar box…

So now I’m getting ready to install the digital boar in it’s place and cut the holes in the top for the lcd, leds, and buttons…

you may notice I didn’t install the pots on the board. That’s because I’m using larger pots that are on the other side of the box (As seen in the first pic). I’ve already rewired the pots so they can run to the digital board, but you’ll notice I haven’t yet wired up all of my ‘chasis-mount’ components (audio jacks, midi jacks, and pots). I put standoffs under the board and will screw them to the bottom of the case once I get everything measured out.

I’m excited to hear this thing in action! I’ll keep you guys updated on my progress.


Cool - maybe you might consider swapping the Display for a red one, might fit better the Color of the Case…

True, I’ll think about it once I get the case finished. I still want one with a keyboard eventually too so I may ditch the cigar box in the future (when I have money…)

Anyways, I do have it fully assembled now and it’s working for the most part, except for a lot of noise leakage and a little bit of erratic behavior. My L7 acts really strange too in some modes. L6 sometimes as well. I’ve taken a few videos, I’ll post them later.

L6 reflects the value of the currently selected modulation source in the modulation matrix. L7 blinks with the tempo. Is that the “strangeness” you refer to?

I have noticed those behaviors and figured they programmed that way since they match the tempo, but there is also associated noise and ‘buzzing’ that corresponds with the LEDs, and while usually the noise floor is tolerable, it gets particularly bad when on the modulation matrix page. I uploaded one of the videos to my server, I’m not sure where the other two went… I apologize for the poor quality of the video, as my phone is the only camera I’ve got :-/

The video is here (in 3gp format)

Alright so the problem has largely disappeared, I think the culprit was just shoddy wiring to external components. I finally have ‘breakaway’ connectors on everything (MIDI in, audio in/out, control pots, and digi-analog board connection) so both boards can easily be removed/inserted and I think it has helped. I also had my pots wired up backwards before anyways.

The only thing I’m unsure of - in the filter section is the range for resonance supposed to be 0-63 or 0-127? My cutoff knob goes all the way to 127 but resonance only goes to 63. The same is true for the other 2 parameters on the filter page.

Now all that remains is to cut out all of the holes and fix the positioning of the boards in place.

Resonance goes up to 63 ; and so do the modulation amounts.