If the unit is a Mark 2a (Rio Car) as opposed to a genuine Mark 2, then the negative spike problem isn't an issue. As I recall, the 2a units are the ones with the diode fix built-in. Empeg guys, correct me if I'm wrong.

Actually, even if I'm right, give me a heads-up so I can make sure the FAQ is dead-accurate on the issue.

And if anyone can supply a drawing/description of how the diode works into the scheme of things, I could add that to the FAQ as well so people could add their own diodes without bugging support.