modifying quasimidi 309 sound extension

Miscellaneous
1

Hi there, I own a quasimidi 309 drum machine with full extension, that are synths, audio out, and drums.

I wondered since the drum epansion is an eeprom from texas instrument (27CO10A-12), if there were any way of changing the sounds offered by the extension. My point is I want to get rid of many of the “electro” sounds provided by the extension, to put my own samples more hiphop and jungle. I suppose it needs a reader writer for this type of chip, but also is there any way to understand after reading how the data are organised, and if it’s possible to get the sounds charactéristic and replace them by my own with same characteristics.

Anybody have any experience doing this, quasimidi brand no more exists so I can’t  expect any expansion that would satisfy me.

Any hints ?

defred

2

Hi,

You can always try :wink:

Preparation: do a recording from the sounds on the expansion rom, you will need it later. Then you really need to dump EPROM contents to binary file. (Wanna DIY suitable programmer: http://w1.859.telia.com/~u85920178/ -> projects -> EPROM circuits). Or maybe somebody can do ROM dumping for you?

Ok, my suggestion is using Awave (http://www.fmjsoft.com/awframe.html - I’m assuming using unregistered version here) to analyse, what ROM dump really contains. For unknown file formats Awave opens a window where you can set parameters for the file - With an trial and error, you should be able to discover the right format, hopefully :wink:

Then listening to the dump, you should find out where different sounds are located, mark start and end points - check the correct playback rate, comparing sounds on the dump to those in the recording made earlier.

Your replacement sounds need to be prepared: Resampled to match sample rate of the sounds on the dump, cut to exact same length ect. - one in a time in unregistered version.

Then you can just save those sounds on right format, and keeping track of the right sequence - and finally you can create your own ROM, by chaining all those together for example with DOS copy command (binary mode).

Audit THAT file on Awave. If it sounds kind of similar like original dump, and it’s on same format, length, there are good changes that you have succeed.

This file is then ready to be burned (of course as binary) in EPROM.. and hopefully it sounds, well, right :wink: Easy isn’t it?

Bye, Moebius

(p.s. I also assumed, that ROM dump isn’t in non-standard format and it doesn’t contain additional data, like loop points, ect.)

3

Right, thanks for the leads, I think I’ll try that when I have some time. What you describe is what I thought to do, thanks for the links for the reader and the Awave soft links. I would really like to find another eeprom of this type to test the stuff before I smash my extension :wink:

defred