PWM on complex audio signals

[Happy Harry]

Hi Don (et al)

There is another interesting feature of the "tone stack".
Reducing all the tone controls to "0" gives virtually no
output... turning them all to "10" gives a substantial gain
boost (over the "5" setting)

So its possible to slap the tone recovery stage with a
much larger or smaller signal, with similar overall
spectrum. Guitarists use this to introduce (or remove)
overdrive from the amplifiers...

I remember now... the tone stack pots are in series...
where the passive "hi-fi" controls are separate, and
in parallel.

Thanks for the refresher !

H^)  harry


>From: Don Tillman <don at till.com>
>To: harrybissell at prodigy.net
>CC: synth-diy at node12b53.a2000.nl
>Subject: Re: PWM on complex audio signals
>Date: Wed, 3 Jan 2001 09:51:07 -0800 (PST)
>
>    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 occurs 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
>

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