PWM on complex audio signals

[Don Tillman]

   From: "Happy Harry" <paia2720 at hotmail.com>
   Date: Wed, 03 Jan 2001 15:58:43 -0000

   Unless I forget my tone controls... the Baxandall control is used
   in a feedback loop, where the "Fender" style passive tone controls
   are just voltage dividers (cut only). So you will have some
   different transient responses.

True, but deceptive...

Passive hifi tone controls are what you'd find on hifi tube preamps in
the fifties, and still today.

I believe Baxendall came up with the idea of placing the tone control
in the feedback loop of an amp stage, eliminating the log pots, the
10-to-1 component range and the insertion loss.  The Baxendall
performs similiarly to the passive hifi tone controls, but there are
some subtle differences.

Leo Fender's tone controls are passive, but very different from hifi
tone controls.  Leo basically has the treble control pan between a low
cut signal and a high cut signal, with interesting and dramatic
response shapes occuring due to the phase concellation in between.
Variations of Leo's tone controls can be found on Marshall, HiWatt,
Vox, Mesa/Boogie and practically all other guitar amps.

There's a "Tone Stack Calculator" here:
  http://www.duncanamps.com/tsc/
"Tone Stack" is another name for Leo's tone controls.

  -- Don

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