Thanks for the replies everyone. There's a fair bit of QSC stuff on Ebay right now for what seem reasonale prices second hand.
I'm looking for solid state clean power at the moment. The responses so far have been really helpful, just trying to get my head round interpreting the power ratings as they're often quoted for 2 ohms, 4 ohms, 8 ohms and then bridged power. I'm guessing, that if an amp says it runs at 500 watts bridged at 4 ohms, then I can daisy chain my 2 8ohm cabs (rated 600 watts rms each) for a 4 ohm (ish) load?
Bass tractor, I'm not sure I fully understand what you're getting at?
[quote name='BassTractor' timestamp='1395754223' post='2405801']
Better start with splitting the bass and/or the cab into two components each. These separates will have a dramatic effect on your sound.
[/quote]
My current setup is: bass -> amp -> 4x10 -> 2x15. I occasionally pop a compressor or my multi-effects (or both) between the bass and amp and occasionally use the effects loop in my amp.