Diodes used to clip for distortion?

[icydash]

Hey guys i decided to build a distortion pedal and ive been looking at a bunch of schematics and it all seems that they used diodes to clip off the top and bottoms of the waveform. How do the diodes do this i dont really understand? I could understand pushing an op amp past the V+ voltage and getting the top to clip, but i dont really get the diodes? A good example of what i mean is: http://www.diystompboxes.com/pedals/MXRDIST2.GIF


Any help would be appreciated, thanks!

[aron]

http://www.geofex.com/effxfaq/distn101.htm

http://www.generalguitargadgets.com/richardo/distortion/index.html

http://www.muzique.com/compress.htm

http://www.muzique.com/lab/warp.htm

[icydash]

awesome thnx