For replacement/substitute parts, see this forum topic: http://www.ladyada.net/forums/viewtopic.php?f=12&t=4610

LadyAda ships with these replacements, with no noticeable sound differences

• 733p instead of 733ap
• BA6110 instead of BA662a

—- SubAtomic has done some analysis of these, and has found BA6110 to be only slightly different, yet perfectly acceptable (perhaps even more desireable: it's a little louder, which can be a useful thing to slightly overdrive the mixer output for a little distortion)..

• 733p and 733k instead of 733ap (analysis)
• BA6110 instead of BA662a (analysis)

—- MomeRath reports that replacing these causes no sound difference:

• Using NTE44 instead of 2SC2291
• Using 2SC945P for 2SC536F

—-

If you find other substitutions that still maintain the original sound, please post your results in the above format…