The cart accesses $DE00 $DF00 for midi and memory.
And here is why MSSIAH and SID2SID fucking suck, if you have a SID2SID board, populated, your DE00 SID is conflicting with Kerberos, so you might run into many issues.
SID2SID is garbage. I made my own SID board. It isn't hard. You said you were into electronics and modifications, so why would you not just get what's needed and build your own, proper board? Relying on a pre-made solution created by a lazy person that half-ased the effort, is not a great option in my book.
The seller said a datel midi interface will be out soon. And then you'll need a cartridge port xpander to plug in cynthcart and the midi interface.
No. DATEL interfaces go in the user port I think. Not sure though because I never seen one in the flesh.
You'd need an expander if you ran Kerberos and Cynthcart. And yest hat's the point of the expander, to support many cartridges at once.
BUT, problem again, this works ONLY if the addresses don't conflict.
You need to be sure that your particular combination of hardware doesn't have overlapping addresses.
In your current setup already, if you put a Kerberos cartridge, your internal second SID is conflicting with it.
Oh and before I forget, one extra note on adding SIDs: they're power hungry, and the more you add, the more strain you can put on the C64 power supply. Knowng that a lot of C64 power supplies are absolute garbage and can kill your computer, I'd be wary of how many I add while using a standard power brick.
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