Re: Which preanmps are best ?
Jimmy,
I'm inclined to agree with some of the others: a wired, dynamic microphone (like an SM58 or Sennheiser e835) is really going to be the best option.
You have fewer places to worry about setting the gain correctly, a wired mic is inherently more reliable than a wireless microphone, AND they're pretty much indestructible.
If you're worried about the mic cable falling out for some reason, use a few wraps of gaffer's tape to fasten the cable around the mic handle...watch other hip-hop videos, you'll see what I mean. ;-)
Then, after all that, do some searching on these forums for "gain structure". It would be a good idea to bone up on that before your next event, no matter what it is.