[sdiy] tonal tilt

[Travis Shire]

> Totally Off Topic.. but I asked this in a guitar amps forum years ago
> and never got a response. I wanted to run my guitar amp "flat", so
> none of the tone controls were colouring the sound.. as though they
> weren't even there. I never knew if the presence knob should be at 0,
> 10 or in the middle.

The presence control is an "active" control since its taking freq dependant
feedback from the output and shoving it back into the phase inverter. You
can never have a truly flat response with a standard passive tone stack.
Even with all the controls full up they will alter the signal (we call it
robbing).

See here:
http://www.duncanamps.com/tsc/