Re: Vintage Marshall cabs question.
Good question. I've always assumed it came along with the introduction of the JCM 800 line, but I'm not sure. I know that the best mod for current Marshall cabs is to
trace the back onto good quality plywood, add levant or black paint, and put some insulation on the back to kill standing waves and vibrations. Not many people do it,
I assume, but that's the easiest way to make a Marshall cab sound perfect.
Particle board on any cab = toneless mush. IMO, the 1936 2-12's sound terrible, since they're all particle board. I had one, and couldn't sell it fast enough.