[sdiy] Notch Filter for Logon's Human-Capacitor Filter

[John Luciani]

On 12/14/06, Aaron Lanterman <lanterma at ece.gatech.edu> wrote:
>      I'm a student in Aaron Lanterman's synthesizer class. I'm working on a
> circuit that allows the user to control the cutoff frequencies of a high
> pass and low pass filter through capacitance with an antenna. However, one
> of the problems I have encountered is 60 Hz wall voltage being coupled
> into my circuit through the antenna. To me, the easiest solution seems to
> be putting a 60 Hz notch filter at the output of the circuit. In an effort
> to avoid inductors,

Here are a couple of things to try before you build a filter ---

* Have you checked all of your ground connections?

* Is the power supply return tied to earth ground? The Theremin
circuit may operate
  better with the power supply return tied to earth ground.

* Is your power supply filtering all of the 60Hz ripple?

(* jcl *)

-- 
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