Just some questions that I have that need answering... 1)What's the difference between tube power amps and solid state power amps? pros & cons... 2)What is the purpose of a power conditioner and compressor in a rig? 3)What makes a pre/power amp setup more appealing than a head? Couldn't you just get a very powerful head for less $$? 4)Bridged power amp...what does bridged mean?