It shouldn’t be all weird stuff, sometimes one needs some simple building blocks. After a bit of experimenting with sending audio from the mixing desk to the modular I found myself short of a way to amplify a line level signal to the audio levels used in a modular. Hence, I thought I build myself an input module with the sole task to take in a line-level and give it a nice boost. It’s a simple module actually.
I’ve put some updated schematics for the oscillator one online. Changelog:
- Changed Linear Ramp output volume so it’s in line with the other ones (R59 to 20k instead of 10k)
- Changed the sensitivity of the coarse and fine knobs (R10 and R11)
- Used an LM4040 to create a 5V reference instead of L7805 and L7905 voltage regulator. I hope this will improve stability when switching octaves.
- Added a potentiometer for the saw animation in
I was one of those guitarists who spend more time with his effect pedals, then with his guitar. I ended up exchanging my guitar for synths when it came to music making. Not really a surprise there, but my love of piling effects together into a huge unpredictable pile is still there, and somehow, even with a bunch of 19″ racks I haven’t been able to scratch that itch. You could use a computer these days, but nothing beats a bunch of wires and noisy electronics to spark creativity. Guitar pedals are nice and all, but do lack in certain areas when you try to use them with synths.
While doing research for the oscillator I stumbled – seems to be a common theme — upon these IC’s. The ICL8038 promises to be a stable oscillator with very few external components. It’s an obsolete product, but I could get a few of them via Ali-express cheap enough to experiment with. Since it offers a sine output I immediately thought about doing some FM type percussion. That way I wouldn’t need 1/v per octave and pitch fluctuations wouldn’t be that much of a problem either. I also had a V2164 quad VCA chip around, so a 4 operators (aka oscillators) seemed a perfect fit. Enough to provide some interesting FM timbres at least.
Since Coolaudio started reissuing old IC’s used in various synths I always eyed the V3340, which is a reissue of the CEM3340 chip as used in many classic synths such as the Roland SH101, Prophet 5, Memory Moog and plenty of others. It’s, in essence, a fully featured 1V/oct oscillator on a single IC and thus takes away a lot of the headaches inherent to VCO design. Things like linearity and temperature compensating are taken care of for you. This takes away a lot of the pain of building VCO’s, in fact, since these IC’s are available again a DIY polysynth starts to become a possibility.