I realise there are a number of factors to this- bass/effects/eq/speakers but am considering trying a few different setups or even a bi amped rig. It I was looking for huge low end - what amps would you think of? Size/wattage I am pretty flexible on, but I want a serious amount of low end rumble. Tube/solid state/MOSFET whatever. Prefer to stick away from any of the digital/emulating amps. Are there any 'holy grail' type amps for this kind of sound? Dirty/overdriven/clean- all good with any of these.