[sdiy] Roland System 700 VCF

[lanterma at ece.gatech.edu]

On Jul 10, 2010, at 4:51 PM, Stewart Pye wrote:

> Since the input of each stage is going into the non inverting input of the OTA and the OTA then goes to an inverting integrator, it is negative feedback through the 22K resistor. However I believe that when using the SSM 2164 followed by an inverting stage, the output is not inverted. If this is true I'd have to either add an inverting op amp stage for the feedback, or add a differential amp in front of the VCA.

Here's something pretty close to what you're aiming at: 

http://userdisk.webry.biglobe.ne.jp/000/024/65/1/VcfSSM0602a.GIF

- Aaron