Hi guys, I'm building a Arduino based step sequencer (8 steps, 3 tracks) for my Eurorack synth. You can find the planned schematic attached.
Some explanations for the context:
- The circuitry from pin 3 of the "CV In" jack serves to detect the audio jack (which works really great).
- R3, R4 and the zener diode are meant to prevent voltages higher than 5.1V on D4.
- The Neo Pixel visualizes the steps, tracks and modes.
- Track1-3 control switches set the steps (hits) on each track.
- Track1-3 output jacks are sending binary gates or triggers (I want to send them to envelope generator modules).
- The prototype runs on an Arduino Uno and I will ultimately implement it on Arduino Nano.
My questions are:
- I tested the voltage regulator circuitry (R3, R4, ZD1) without having it connected to the Arduino. With an input of +12V it resulted in ~5V, which is fine. When I applied -12V, I still measured around -0.7V. Can this negative voltage already toast the Arduino and if so, what would be an improved circuitry from your perspective?
- Would you recommed buffering the output (with a transistor, op amp, etc) before sending it to other modules instead just having R10-12 with 1K Ohm each or is it fine as is? When I tried it with one output on my Eurorack envelope generator, it at least worked.
I thank you in advance!