Diodes in SD-1? What do they do and replacements?

[Hawkwind]

Hi. I have searched but i can't find how the different diodes in a sd-1 effect the sound? Im modifing mine but im not sure if what diodes i want.

Correct me if im wrong. One of the diodes effects the clipping on one side of the signal and another the effects the other side. What does the third in the SD-1 do? Or are they linked i any other way?

Maybee its just easier to tell you want i want to get out of my mod but i want to learn something.

I want to get out a warm overdrive. Like a overdriven amp, only slight overdrive.. Not distorsion. (I have a Guvnor for distorsion) 

Want should i do with the diodes? I prefer if i could use the diodes i have at home. The stock of course and 2x 1n34a and 2x 1n4001.

But if you think it will be much better with any other diodes tell me.

[BAARON]

D5 and D6 are in series with each other to make the clipping assymetrical.  Check your PM inbox for some tips and information that might help you mod your SD1.

[cmog]

I wrote a little something for www.effectsbay.com, and my website.
I tried to explain everything as simply as possible but you could get a lot more in depth answers here from Mark and RG.
I think this will answer your question...

http://www.cubisteffects.com/2010/01/mod-it-yourself-part-2-diode-clipping/