SFX Sound Expander FM module: compatible w/ C128?

[ruthven]

I've wanted one of these for a while--now I might have an opportunity to purchase one, but I understand that they were made in Europe and pretty much only distributed there...  I'm wondering: do they work with NTSC machines, and do they work with C128s?--I don't currently own a working C64, but I will soon enough--just a matter of time...

[commodorejohn]

I've never had any trouble using mine with my 128. The only problem with it is that the registers for the keyboard add-on overlap with the REU registers, so you can't use both at the same time =/ But the FM chip works like a charm!

[ruthven]

Thanks--just wanted to be sure and now I'm definitely going to try to get it.  Is it that big multiple octave piano keyboard that you're talking about overlaping with the REU registers?--do you suppose this is an NTSC/PAL compatibility issue or a C128/C64 compatibility issue?--not that it much matters--the auction I'm looking at doesn't include the keyboard anyway, though I had thought of purchasing one separate--not only to play around with the FM module, but to try to incorporate as a controller for my own synth program I'm working on...

[commodorejohn]

Yeah, it's the piano keyboard, but the registers in question are in place whether it's connected or not; any time you have the Sound Expander plugged in, the REU won't work. It doesn't have anything to do with NTSC/PAL or C64/128; it's just that the registers reserved for the keyboard block out the REU registers.

[ruthven]

That seems weird to me because I thought the keyboard was intended for the Sound Expander module specifically.  According to an article I read (http://www.floodgap.com/retrobits/ckb/secret/sfx.html), the keyboard is part of the SFX series and plugs directly into the sound expander module (see very bottom paragraph on that page).

Perhaps you have a different keyboard...?--there were several made apparently, all fairly rare--maybe you have the "Commodore MIDI Keyboard"...?

Or maybe I'm just confused as to what you're talking about--what exactly are the "REU" registers?

[commodorejohn]

The REU is the Commodore Ram Expansion Unit, the thing that you can plug into a C64 or C128 to give it access to more memory. That's the thing that doesn't work with the Sound Expander, because the registers for the Sound Expander's keyboard add-on overlap the registers for the REU, at least if you plug the REU into the Sound Expander's pass-through port; some of the multi-cart selector devices out there might be able to give the REU first dibs, I dunno. But if you didn't know what the REU was in the first place, then it's no big deal and you shouldn't have any problems.

[ruthven]

Ok, so I was confused on what you were talking about.  Thanks--that clears up a lot.  I thought the REU had something to do with the keyboard or the module itself and that you were telling me that one wasn't compatible with the other...

Ram Expansion Unit, huh?--shows how much I know about Commodores and their peripherals... 

I don't have an REU anyway so I guess I shouldn't run into any problems.  Thanks again!

[commodorejohn]

Yeah, REUs are mostly for Commodore power-users, generally for use as a RAM disk, or with more modern Commodore software (GEOS, etc.) It's not really necessary for anything old-school.