Pa system is the win as mentioned, dont skimp on mics, its not worth it.Go for something like a poor mans sm57, the pg57, i have one and its pretty damn nice, cost me about $50usd new.
On the pre amp side of things,BE VERY DUBIOUS about any small pre amp that contains a tube, most of them are a complete con as they dont give the tube anything close to its required plate voltage (if any at all, some just send the 6v ish to the heater, the tube itself is not in the circuit at all) to be of any use.The guitar use pre amps that contain "tubes" that are designed to produce distortion (ala mesa v-twin) are also mostly cons, they use whats called "plate starvation" to create the distortion, not driving the tube even at its recomended rate let alone into clipping!Chances are if it runs of a walwart/plugpack, its a con!
For guitar amps i am tube all the way, but mics, you really are just trying to reproduce the sound allready created by guitars,amps,vocals etc, not wanting to colour it at all,so a good SS unit is more than adequate. Bottom line, if it sounds good and you like it , buy it, but dont buy it because its got a "tube" in there.
