Oh your panel is so nice, I do need to brush up on me Inkscape skills.
Are you sure there’s enough rail clearance at the top? It might be your screenshots but it does look a bit tight.
3 Likes
Some sounds 
8 Likes
I’m also planning to build a sub oscillator based on the Electric Druid study. I decided to use the square/pulse outputs only but install a buffer for the input signal. My question is; is it okay if I add a voltage follower praller with the original circuit?
For a ±12V supply, I’ll use the resistor values for the buffers as defined above by Rich, and a 7905 for the -5V reference. Thanks for that!
1 Like
Not familiar with the word “praller” but if you’re asking if the voltage follower shown is OK, yes, more or less. I don’t think the 1M pulldown is doing much of anything — there already is a 253k path to ground. Note that if the signal on the non inverting input goes beyond around -7.5 V the op amp can go into phase reversal lockup, and that absolute maximum voltage on the non inverting input is the rail voltages, so connecting the non inverting input directly to an input jack can have its risks. But overvoltage probably isn’t worth worrying about if the rail voltages are as high as anything else in your setup, and phase reversal is not damaging, just annoying — it starts working again once the large negative voltage is removed — and such large negative signals are unusual in most synths, so that may not be worth worrying about either. Still, I tend to put a resistor, maybe 1k, between the jack and the non inverting input on the theory it’ll mitigate problems with overvoltage.
As said above, something like an LM4040 shunt reference is in principle more appropriate than a voltage regulator, but presumably high precision isn’t needed here and an L79L05 is even cheaper than an LM4040, so that’s fine.
1 Like
Wow, thanks for the detailed explanation and the fast reply! I’ll omit the 1M to GND, and add a 1K after the input jack.
(I meant to write parallel, seems like my editor is out of office.)
Hey, @BlackDeath. Nice project.
The sound samples you made reminded me things like How to Destroy Angels or NIN.
I know it’s been a few years since you worked on this, but do you still have the final schematics for this project?
Thank you!
3 Likes
Sure thing, I’ve opened up my github repo with all my circuits/panels:
However, I’m not too happy with… any of these, to be honest. There’s a lot of ‘learning by doing’ here. I find that XORcist has a tendency to die when it tries to process more complex audio signals. It’s finnicky. I’d recommend building it on bread/strip board first and tweaking to your own taste.
4 Likes
Great. If I can get those “slightly distorted sub punches” you got in the demo, I’ll be happy.
Anyway, I’ll put this on the breadboard and poke around to see how far it can go.
Thanks a lot.
1 Like