I haven noticed the -51 sound board running future spa software has at least one sound effect that will speed up or slow down depending on what 6802 chip is installed. The sound effect is the game start noise. Some chips it is very slow and takes 2 seconds to complete the effect. Other chips it takes 100ms or so to complete.
I have tried numerous different chips and STM, SG, Moto, Hitachi all will show some variances and I have not yet identified a pattern, but chips in the same lot codes will act all the same way. Every SG Thompson made in France are always super fast type for example. Hitachi I don't know how to decode their date scheme but usually these are "slow" type. Motorola varies with newer the date code more likely to be "fast type" but not always. Not enough data to tell a pattern yet.
As far as I can tell this only effects Future Spa's game start noise and maybe a few other sounds in an insignificant way. Has anyone else noticed any other -51 sound effects vary by what CPU chip installed? Any idea what is going on to make some chips go fast and others slow? Seems like there are some undocumented differences cpu chip to cpu chip depending on date code, manufacture plant, and/or brand.
Here is an example if you want to listen. I did not capture any "slow" ones.
"medium speed"
"super fast speed"