[sdiy] E-Drum antics, EPROM data dumping

[harrybissell]

Its possible that Grant Richter's excellent "Wave256" program that
he did (or had did :^) for the MiniWave might possibly give you
a clue as to what the data might look like. It is an 8 bit system...
It does expect a 256 x 256 data set but WTF an hex editor could
provide some chunks of that size...

H^) harry

Metrophage wrote:

> I decided to take a break from my MG-1 modifications (and heaps of
> repairs...) to check out these modules. The E-mu E-Drum was a version
> of the Clavia Drum Plate, 8-bit percussion ROM-pler with a few
> articulation and tone controls, the top is a piezo drum trigger pad. I
> bought three of these, supposedly broken, off of a guy for $20. One
> version 1.1 and two version 1.2.
>
> Only thing which really needed repair were the crap Piher plastic pots.
> Bad news putting plastic pots on anything meant to be played with a
> stick! Also, to keep the drum pad on, the units were wrapped in many
> turns of 15-year old packing tape. I peeled off the tape and scrubbed
> the cases with alcohol to reveal the beautiful baked-enamel finish,
> scrubbed the PCBs, and replaced the broken plastic pots with 1/8"
> sealed pots.
>
> These things feel quite nice! The pad feel is quite something: the
> steel chassis is cut out, and epoxied over it is an aluminum plate
> covered with rubber, with a piezo disk epoxied under it. The kewl
> articulation feature is that it is very velocity sensitive. Sounds to
> me like the pitch increases with velocity, though this might just be
> because the higher frequencies are more audible with increased
> amplitude.
>
> Between my three units, I have only two ROM cartridges: "Electronic
> Snare 1&2" and "Gong". The cartridges are basically a 256k ROM on a
> PCB. Since I was just kicking myself for not getting VCDO parts in a
> recent purchase, I am going to tinker with these units to hold me over.
> I assume the main difference is that an ordinary waveform VCDO for
> general-purpose synthesis is induced to repeat its data over and over
> in relation to a clock VCO, whereas the longer drum samples are just
> read out once upon recieving a pulse.
>
> I just got a "Willem" EPROM reader/burner PCB recently, so I figure I
> should use it to try to rip the data off of the ROMs. By studying the
> ripped data I hope to understand how the audio data is formatted on
> there. But even if I can extract the data off of the ROM... I'd expect
> it'd look like hex or binary gibberish to me. I really wonder how I am
> going to recognize audio data by sifting through the contents! Time to
> get my windoze machine out of the mothballs and onto the bench!
>
> CJ
>
>
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