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

[Don Tillman]

   > Date: 14 Dec 2006 11:16:40 -0800
   > From: Don Tillman <don at till.com>
   > 
   > Do a balanced version of the filter. 

By that I mean...

Build two identical filters, put a positive source signal into one,
put a negative source signal into the other, use a differential amp to
combine their outputs.  The 60Hz hum and noise is common to the two
and will mostly cancel.

That's the theory; in practice it would probably work out to a single
filter, but a filter of a balanced design, where the tuning
capacitance is between a positive and negative signal, instead of
between a positive signal and ground.

  -- Don

-- 
Don Tillman
Palo Alto, California
don at till.com
http://www.till.com