Ok then. I always thought that the sound differences between DMG and MGB are caused by amps and other stuff and not by CPU. Guess there is no actual data on this anyway...
There is some data. For example, Herbert Weixelbaum's sound comparison.
http://www.herbertweixelbaum.com/comparison.htm
There's also an interesting (though not 100% confirmed) theory about the DACs of Gameboys described in the GBSOUND document.
PARTIALLY VERIFIED:On older versions (pre-DMG-CPU-05?) of the DMG, the scale
of
the DAC used on the various channels is semi-logarithmic instead of truly
linear. Later Gameboy models (MGB,SGB,CGB,GBA) used either better pull-up
resistor/capacitor and/or analog output DACs, and are almost perfectly
linear.
(Thanks Jeff Frohwein)
Here are some scales for demonstration:
TRUE Logarithmic:
0---------------1--------------2-------------3------------4-----------5----------6---------7--------8-------9------A-----B----C---D--E-F
TRUE Linear:
0--------1--------2--------3--------4--------5--------6--------7--------8--------9--------A--------B--------C--------D--------E--------F
Semi-Logarithmic:
0-----------1-----------2-----------3----------4---------5---------6---------7--------8-------9-------A-------B------C-----D-----E-----F