[sdiy] Yamaha IG00159 internals

[Mattias Rickardsson]

Yamaha's envelope chips are odd in the way they use an extra VCA chip
just to implement the envelope itself. I'd expect them (all of the
Yamaha IG chips) to be very simple inside. The envelope chip probably
just consists of the little logic state machine taking care of the
Attack/Decay/Release envelope phases, and routing the input CVs
correspondingly, letting the external extra VCA chip do the slopes.
Maybe this chip is already analysed and copied to standard components
of breadboard?

/mr


On 17 January 2017 at 14:05, Nicholas Keller <niroke at tampabay.rr.com> wrote:
> Does anyone know of an internal diagram for the IG00159 amp EG chip?  Or has someone made a stand-in circuit for the chip alone?
>
> Thanks
>
> Nick
>
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