Hey! I've got a closed back Marshall Combo amp, it's an MA50C, i know it's not the best but i've got it so there you go. Basically i was wondering if i take the back off it whilst playing would it give a better sound?

Recently played a Fender Hot rod Deluxe III and it was awesome and i saw it's basically a 3/4 closed back or near enough that. I need it for gigging to be honest but i can't afford to throw away £700 at the minute.

So yeah if i took the back off or made it half and half open/closed, do you think it could improve the sound?

I don't see why trying would hurt. But I doubt it'll improve it enough to fix the tone of that amp.
Peavey 6505+
Fender Hot Rod Deville 410
Fender Telecaster Blacktop
Gretsch G5120
Put some new pre-amp tube in it and your tone will get better. JJ ecc83's and Mullard 12ax7's are pretty nice
2002 PRS CE22
2013 G&L ASAT Deluxe
2009 Epiphone G-400 (SH-4)
Marshall JCM2000 DSL100
Krank 1980 Jr 20watt
Krank Rev 4x12 (eminence V12)
GFS Greenie/Digitech Bad Monkey
Morley Bad Horsie 2
MXR Smart Gate
A new speaker will do a lot for the sound if you haven't swapped it out already.
The other guitarist in my band uses an MA50 as a backup for his TSL and through the 1960 cab, it sounds a lot better than the stock speaker. Still not great, but certainly good enough.