Here's the problem.
It doesn't sound low quality. It sounds like a solid/good recording, of a marshall DSL 1x12 combo
I think you, perhaps, are expecting your DSL combo sound like something it isn't.
There's no magic recording secret that's going to make your dsl combo amp sound like a 5150?
Honestly, I think your best bet would be experimenting with IRs to figure out what kind of mic position+cabinet/speakers give you the results youre looking for - that would be the most dramatic change without an entirely new rig.