I'd like to add a tone control to my LaVache I'm working on. Would it be difficult to add onto a pcb based circuit? I found http://www.muzique.com/lab/tone3.htm as reference...
That style of tone control would not be a good choice as an add-on because it will cause some loss of output. You would probably have to have a recovery stage after it. Not impossible by any means, but significantly more complicated.
I would look at the SWTC for this (stupidly wonderful tone control). It's an easy tone control to implement and has minimal/no effect on the output volume.
http://www.muzique.com/lab/swtc.htm
I read a bit about the Big Muff tone stack (ie it's simple & passive)--Is there an active version that doesn't lose so much gain, but still retains that Muff tone knob quality?
I suppose I could always just run an eq pedal before or after it :-\