monitor a guitar signal strength, then output a DC level?

[HankMcSpank]

Have you considered using the NE/SA 572 chip? I think to propr do such a job with controller you need a fast one like dsPIC or better a DSP processor.

PIC'c do not have many resources for analog processing.

Ioannis

That's a nice little chip, but alas the minimum VCC is 6V. (I'm tied to 5V)

As it goes, in my config, I'm not placing that much in the way of demands on the PIC - it's simply sampling a rectifed/smooth guitar signal to get a handle on the signal strength. The PIC then either pulses up/down a digital pot accordingly - as simple as simple can be.