Knight-Allied Fuzz

[Mark Hammer]

I threw one of these together over the weekend, in a 1590A.  Nothing especially attention-grabbing on its own, but I like what it does to the overdrive channel on my SS Fender amp.

I was wondering if the input could be improved, and possibly have more range of adjustment  if we simply flipped the resistances around.  So a 100k input resistor and a 500k pot.  That would permit the original arrangement of 470k series and 100k to ground to be replicated, but allow other arrangements.  Or is there something "special" about the base of Q1 never seeing an input series resistance less than 470k?

Yes, I know I could simply do the swap myself, and report back, but 1590As are such a pain in the neck to work with, I'd rather have some justification to proceed (or not) beforehand.

[anotherjim]

If pot is off board - change the pot and bypass the 470k with 150k - may be able to avoid too much fiddling.

[Mark Hammer]

So, I did the swap.  I decided to paint the enclosure, so I had to remove everything from it anyway.  That made it easier to swap out the parts.  Using a 100k fixed resistor and 500k pot made it possible to increase the drive a bit more.  Nothing misbehaved.

Not that there is any shortage of two-transistor fuzzes and distortions out there, but this one is a bit of a historical relic, in a way.  Some might like it for itself, and some may like it the way I do - as a booster that conditions the signal in a manner that extracts nicer amp overdrive.  It may also do nice things to other overdrive boxes in series.  Not that I have the chops for it, but feeding my SS amp's diode-based overdrive with the unit got me a nicely compressed tone, suitable for Allan Holdsworth legato runs.