Take your head to a shop and start trying it out on better cabs. Never underestimate the speaker cabinet and its influence on how an amp sounds. A Bogner XTC through a no-name shoddy 3
4x12 with cheap speakers will sound still sound like crap while an OK, not great but not bad, amp through a Mesa 4x12 or something higher-end will sound A LOT better. The VK is an alright amp, and a good platform for mods that can really turn the amp into something cool for a good while until you can upgrade to something that sounds really good out of the box. A great cab will last you a life time, and then all you'll ever need to buy for an amp is the head.