Peterson Strobostomp
Exotic BB Preamp
Electro-Harmonix Deluxe MemoryMan [He uses 2 of them, one set to 500ms the other set to 350ms]
Chandler Tube Driver [i think he only uses this with his Mesa Boogie Stiletto]
Watch Andy demo his whole rig here!
Wait! wrong picture!
Here y'go, Spencer Elden all grown up...
Read more:
http://www.mtv.com/news/articles/1598985/20081110/nirvana.jhtml
Check out Yngwie Malmsteen's home studio!