How to do diode selection switch

[Mark Hammer]

Which I gather is the basis for different pedal designs employing different series resistance values leading up to the diode pair to ground.  It would also be the basis for some designs using variable resistors in series with a diode pair to produce "soft" clipping.

That might be the intent but it really can't make a lot of difference. Going from 1000 ohms to 500 ohms in a typical diode clipper would change the peak clipping from 0.62v to 0.65v... less than 0.5db and inaudible to most of us.

Also consider that most of the opamps used in distortion pedals have limited current sourcing abilities and it becomes even less likely to be significant to the sound.

Best regards, Jack

ps: let the youngsters do the snow shoveling! 

One of the youngsters is in another country today, and the other is at work.  But happily, Mother Nature is doing some of the heavy lifting today.  First time in a long time that the temperature has been above freezing, and I can actually see pavement!  Huzzah!

[Antonio1963]

 I soldered sockets into the board so I could try different diodes. Instead of going with the switch idea. I tried leds, germanium, and silicon diodes. I even hooked them up for asymmetrical clipping. Maybe it's my ears but I really could not hear much of a difference.