I don't really have much info on it besides the "gd", and google didn't help. It's a decent sized solid state that my dad found.
I'm not saying it is but alot of amps have a badge just slapped on there purely for the coolness of it.My drummers dads P.A has a marshall badge on each speaker but they are definatly not marshall.
But any way yours has right kind of knobs and plate.
So where abouts did your dad find this?
Seagulls,the chicken of the ocean.

Originally posted by Gunpowder:
Everyone just jumps on the bandwagon and gives the same advice in these situations. You know what? I'm going to be different. Call the firemen.
a look at the back would be nice...IF its really a marshall, run the serial over at marshall.com and they ll tell you.