This ad is unfortunately all that we know about the very confidential Pro-Bass rack.
It does exist: Tom Scholz owns one for Boston, and some happy-fews managed to have it in hand.
But only a handful were made, and the Pro-Bass is virtually impossible to find and buy.
As of what we can see on the front-plate, the basis is certainly the Bass Rockman headphone amp circuit, with additional filters and EQ's.
Copyright Rockman.fr 2008