[sdiy] Synth Chips (OPL)

[Nils Pipenbrinck]

Byron wrote:
> Yamaha have also made several things like this.  There are the notorious
> OPL3 & OPL4 (anyone care to refute those part numbers?) FM chips, which
were
> used on a lot of pre-wavetable PC sound cards.

That's true.. I have a lot of these old OPL-chips on broken pc-soundcards,
and a couple of years ago I even wrote a little opl-sequencer program on the
pc. I did a lot of weired sounds with them. The trick was not to use one
operator-pair per voice but all the 11 voices of the chip for one sound
(e.g. driving that thing in monophonic mode).

I wonder if anyone knows how to use these chips in selfmade circuits.. I
don't have found a datasheet on them anywhere. It shouldn't be that
difficult to build a small midisynth with them. Basically I expect nothing
more than powersupply, data and address busses and an audio-out.

Nils Pipenbrinck