Yamaha CS80

> No, the reason was because the chip was designed from organ
> tech. The 8th channel was assigned to the pedal board.

An organ pre-dating 1974 with dynamic allocation of voices ?
Are you sure ?
The GX service manual clearly shows the purpose of the SW 7or8 Tone input is
to disable allocation of voice 8 on the YM22401 KAS IC.

Cheers,
Colin