How do bypass the SNES audio low pass filter on the pcb?

[magno]

Oh right, forgot about the latter, although that guy did the entire system in a FPGA.

Seriously?? And who is this guy? Where can I find his project?

[Sik]

Here you go. There's the obvious catch though, it's good enough to get Megaman X to run but that doesn't necessarily mean that it behaves 100% identical to a real SNES (i.e. it's in the same situation as emulators). This is the biggest issue here, if one were to make a clone of the SPC700, we'd need to ensure it behaves exactly the same as its original counterpart in every single regard, or eventually we'll hit something that won't want to work with it (but works just fine on the real thing).

So yeah there's that. You can recreate it with a FPGA, the issue is being able to make a good clone.

[magno]

Here you go. There's the obvious catch though, it's good enough to get Megaman X to run but that doesn't necessarily mean that it behaves 100% identical to a real SNES (i.e. it's in the same situation as emulators). This is the biggest issue here, if one were to make a clone of the SPC700, we'd need to ensure it behaves exactly the same as its original counterpart in every single regard, or eventually we'll hit something that won't want to work with it (but works just fine on the real thing).

So yeah there's that. You can recreate it with a FPGA, the issue is being able to make a good clone.

Absolutely fascinating! It's a pity that no source code is available, although I suppose it could be used to make clones if it would end up in the wrong hands...

[tepples]

Perhaps what's needed next is some logic analyzer traces on the sound RAM.