[sdiy] low voltage filters

[Chris McDowell]

Howdy list! 

Wondering if anyone is aware of, or has any tips towards, some low voltage VCF designs. I've seen reports of people using LM13700s with a single 5V supply for VCAs, and their one-off forum posts made them seem happy, heh. I realize this would have very little headroom. I've also checked out Hoshuyama's site, which has a few battery-powered designs. Some things I've considered: 

- Perhaps LM13700 just works at 5V ¯\_(ツ)_/¯ (avoiding breadboard as long as possible…)
- Discrete OTA with BJTs
- MS-20 Style, like the monotron 
- Vactrol, H11F1, or similar 

The point of this is that I have DCOs and ADSRs working wonderfully in a 3.3V environment. Some dirt is okay, I say. Super ideally, I want to implement an SVF with a single 3.3V supply, suggestions toward reality / sacrifices are welcome. I imagine this would work fine with vactrols, but I don't want to design anything with parts I can't buy from mouser, hehe. 

Cheers, 
Chris