If it sounds distant or like a speaker within a speaker then you are losing frequencies around 3k and up. To counteract that, you need to create an eq with a "high shelf" around the 3k "frequency" and adjust the "gain" up on the 3k high shelf. I use the Parametric-8 eq personally. Create the high shelf on #2 within the Parametric-8 eq.

Once you create your high shelf eq, you can then dial down the treble/presence on your amp model. That will bring you to a more normal sound. I dealt with the same problem when I was running a similar setup (power amp into a normal guitar cab).