Yesterday a friend visited me with his Solton X1. He is very happy, but I found out some sounds do not sound OK (eg distortion guitar is far too distorted....some others sound similar)

We did an upgrade to OS 5.0, but I think he needs a full OS version to get rid of this problem.

A full version 3.x or 4.x will do ?
Who is able to help my friend ?

Thanks,

Roel