The early Roland VS2480's suffered from a simple design ommission, resulting in a noticable increase
in harmonic distortion at stronger input levels. It is not a preamp fault per se, as even with the preamp set at minimum, one can
induce the distortion with a strong enough input signal. The technical problem is that the Preamp Signal was not properly biased
before it was presented to the A/D converted chip
Click Here to download a self-extracting ZIP of the document I followed to perform The Fix.