[sdiy] loading Drum Machine sample data..Yamaha RX-5

[Scott Nordlund]

> I was wondering if these cartridges are just large eproms? Would it be possible to find a way to hook up wires to the connector and get sounds in somehow?
> 
> I have always wondered how this technology works. I know that some other drum machines, people swap out the eproms and load in new sounds. I just have never heard of this for the Yamaha.
> 
> However..someone did at one time make an 808 sounds cartridge for this machine and it was not Yamaha so it must be possible.

The cartridges are just EPROMs, but not the same as "classic" designs like the Linn Drum or Oberheim DMX. Those machines store one sound per chip and use a counter to increment through the chip's address range when triggered. The data outputs then drive a DAC to produce the sound. The RX5 is different, since it stores multiple sounds on one or two ROMs, and in a different sample format. You'd have to dump one of the ROMs and do some hacking to find how the samples are stored (DPCM?) and identified (names, start points, end points, loop points, probably also initial sound parameter and pad assignment data, maybe more), then create your own data  to suit your new samples. It's not trivial. Probably there's a lot of staring at hexidecimal and burning numerous EPROMs that don't do what you think they should. I think there's data on the Alesis HR16's ROM format; you could look at that for inspiration.