"Clean"Driver for AMZ Presence Control?

[Carlos]

Hi everybody!

I want to use the AMZ presence control type 2 oin front of my amps to tailor my lead sound. I don't want to use as a tone control AFTER a distortion unit.
Which driver do you recommend? Jack?
It shouldn't add too much noise
Regards

Carlos

[Mark Hammer]

Here is what you do.

Make ourself a Big Muff Pi......BUT......

....leave out the clipping stages.   So, instead of going from the collector of the first transistor to the 1uf cap and the "Sustain" control, you go immediately and directly to the junction of the 39k resistor and .004 (.0039uf) cap at the "head" of the tone control section.

Since the BMP tone control network (which is the core of Jack's "presence" paper) involves passive signal loss, you follow it up with a gain recovery stage....which the BMP fortunately just happens to have.  There you have it.  A clean booster stage with treble/bass tone control and a volume control.  Two transistors, two pots, and a small handful of passive components.  Use lownoise transistors like the 2N5089 or MPSA18 or 2N5210, and you should be fine.

Now that it occurs to me, this provides the basis for a decent clean booster using the Tonepad BMP (Gran Mango) PCB layout.  Just leave out the appropriate parts, run a jumper from the Q1 collector  (where the '+' side of that 1uf cap would normally go) to where the Q3 collector normally would go (or the appropriate end of one of the two resistors or 2 caps), and you're done.

Whether it is as "clean" as any of the other cleanboosters is another matter, but the point is that the first and last transistor stages in the BMP are not intended to produce distortion by themselves so they can be easily co-opted to suit this function.  Of course, if you're building from scracth, sticking the BMP tone control and gain recovery stage after a FET or MOSFet input stage booster might be better in terms of providing a nice high input impedance and better retention of high end.