[sdiy] SSM2164 Phaser - another way?

[Donald Tillman]

On Feb 19, 2014, at 2:17 AM, Mattias Rickardsson <mr at analogue.org> wrote:

> The signal input of the 2164 is essentially a virtual ground, so your
> 30k+2164  becomes essentially a constantly grounded 30k.

That's the thing...  At high gain settings almost all of the 2164's diff amp gain is being steered to the output and almost none is feed back to the input, so there is not enough loop gain to consider it a proper virtual ground.  The input impedance of the 2164 will rise at higher gain settings.

(Whether or not this a good mechanism for a phase shifter is another matter...)

  -- Don

--
Don Tillman
Palo Alto, California
don at till.com
http://www.till.com
650 888-9632