Blue Clipper

[Fp-www.Tonepad.com]

I've found a couple of blue clipper schematics online:

http://bryant02.home.att.net/schematics/blueclipper.gif
http://www.montagar.com/~patj/bclipper.gif

They almost the same, except for the 240k (2.4k in fuzz central's) resistor at the inverting input of the opamp...

I have simulated the circuit and with the 20k bias resistor it doesn't work, I tried 200k and it works correctly.

The 240k gain resistor sets gain at around unity, and the diodes don't clip.
With the 2.4k gain resistor the opamp has a gain of around 36dB, which really squares off the wave before it gets to the diodes. The opamp is clipping so hard one could wonder what the diodes are there for other than lowering the volume.

Can somebody provide a correct schematic, or can we make some guesses on the questionable parts?

Fp

[mrsage]

http://www.runoffgroove.com/newclipper.html