sd1 mod question

i forgot where i read this on the net, but it calls for a small cap .47 uf across D5. what does this do to D5? anyway, with this mod, the gain/drive in the sd1 increased and it sounds like a ts808 to my ears and i like it.

found out where i read it- at the kramer forum. but the mod called for the cap across d4, not d5. so i di it wrong but i like the results. i think the cap partially or fully cancelled out d5, making the pedal symmetric.