My understanding is that Sound Blaster 1.x does not need a -5V rail whereas the 2.0 does. Seeing as the 2.0 is basically the same card (albeit a bit more integrated) using a DSP Ver. 2.x - why is there such a difference?
Retronautics: A digital gallery of my retro computers, hardware and projects.
I don't know exact details between these revisions but it may come to either different chips used (the ICs are more integrated after all) or it could just just be easier to use -5V while designing more compact board layout. They probably didn't see it as a problem as -5V rail was standard back then and very common. But I would definitely like to know the exact reason too.
SB 1.x uses zener diodes to create filtered 5V for op-amps. On SB 2.0 op-amps are powered directly from 5V rails. Both sound ok though, maybe i'll try measuring their noise someday (i've got both snark barker and newly made sb 2.0).
