[sdiy] Steiner filter mods

[HOSHUYAMA]

Hello List,

I also built a Steiner-style filter with simple modifications.

Schematic:

  http://houshu.at.webry.info/200511/img_1.gif

Constant current source Q2 reduces common-mode gain of the
differential amplifier to almost zero, resulting in far less
CV feedthrough.

Another modification is the output point to the buffer U1.
Response of the resonance pot is more like Korg MS20.

I also used a diode limiter as Yves Usson.

Sam HOSHUYAMA
Saitama, JAPAN