What will get me the most accurate JCM 900 tone? ADA-MP1 or JMP1?

[hippietim]

Just get a JCM 900 head - you can get them stupid cheap these days. The 2150 is a ridiculously loud amp with KT-88's that is not going to sound much like a JCM 900. I used to have a 2150 and it is very unremarkable sounding until you are pushing it really hard at which point it sounds pretty damn good. A Boogie 2:90 is going to be a lot better for a Marshall vibe.

Hauling around a 16-space rack SUCKS - I'd rather have a 6 space rack and a head.

[markD]

the application is important. i can tell you, as a guy that gigs regularly, having a huge rack and a couple cabs will be a PITA. i use a head, a 4 space rack and a single 4X12 with a midi controller for the rack, the switcher for the amp, and a small pedal board with my wah and phase 90...it is a fucking nightmare to set-up in 15 minutes.....

go with the minimum of what you REALLY need onstage and you will be happier.

[horns666]

to the original question..

...JMP-1