Guitar sounds, hopefully I have come to the right place..

before you sell it, try recording just the direct preamp signal and download some impulses of different cabs on this forum to apply to it.

if the impulses sound much better, then it's either the power amp section, cab, or mic positioning you should try to work with.
if using impulses gives you similar or worse results then it's either the guitar, pedals, or the preamp settings.
 
Well he mentioned it doesn't have a line-out, however that echo send should do the trick for getting a preamp-only signal