wow .... totally different!
Not sure which I like best but they both rock.
If I were handed a git and 5 minutes to showtime I'd add a little presence/treble to the 2204 ..... or if I had to use the 2203 I'd almost immediately cut a bit of highs.
Yup, and that's exactly what I do. I don't ever run the bass and mids that high on the 2204, and don't ever run the presence and treb that high on the 2203.
I've been learning about plate voltage on these amps and why some of these 2203/4 amps are bright as hell, and why some are dark as hell. And it almost lines up with the cosmetic split between the JMP models and the JCM 800 models. The circuits are the same, except Marshall pulled a transformer fast one on everybody around 1980 that roughly coincided with the birth of the new-look JCM 800. My JMP 2204's plate voltage is in the lower range which, according to my crack research, causes these amps to sound darker, woodier, creamier, browner, and whatever else dumb sound-to-word adjective people like to use. But many people with JCM 800 2204s, same circuit, complain of the amp blowing their faces off with high end. What's the difference? Plate voltage. My JMP 2204 has a plate voltage around 400 VDC, which is low-ish in Marshall world. The JCM 800s have way higher plate voltage, like in the 450 VDC range or higher, and supposedly that causes those amps to be brighter, tighter, punchier, etc.
But I tend to like that tighter brighter sound better for my kind of music, so I'm looking into a simple mod, if there is one, to raise my JMP 2204 voltage to the preamp and see if I can tighten it up a little bit to sound more like
the JCM 800 versions..
I'm still doing my homework though, so I may have this all wrong.