So I had a go at switching out the 'pre' amps with the standard ones but I couldn't hear much of a difference. I also downloaded Peter Hanmer's free patches from his website (http://www.peterhanmer.co.za/hd500x.htm) and they sounded pretty thin and fizzy to me too. I'm aware that his patches at optimised for direct use and I'm going into a power amp and cab so it might not be ideal.
So far the best results I have had are with the Mahadeva model, which I think is the Bogner Shiva one...it comes closest to having the body and depth I am used to from the Switchblade. I'm still not feeling like I'll be able to switch over to using the digital models fully. They just don't seem to fill the cab, if that makes sense...the straight valve amp just feels much fuller and open.
Does anyone use the HD500 models via a power amp and cab for live use? I could probably do with some tips.
Is the Helix that much better?