[sdiy] Ladder filter analysis

[Tim Ressel]

Hi,

I was talking to a guy who was trying to eliminate control voltage feed through on a filter when it dawned on me: the differential nature of the Moog transistor ladder filter design eliminates CV feed through. The audio is balanced on the two sides of the ladder but the current is common mode, so it gets cancelled at the differential amplifier.

Moog really was a clever guy.


Tim Ressel
Circuit Abbey
503-750-9331
timr at circuitabbey.com