Pre-amp with a wireless mic - question

Question:

Talking about live sound here:

I am using the Samson wireless mic. The belt clip has what I believe to be a very basic pre-amp. Now, this is not a high-end system in the least bit...but it actually sounds quite decent. My only complaint are in the highs, where it seems to be a bit louder, and it does need a little warmth.

So, I would like to add warmth in the sound, as well as control the highs. My initial thought is some sort of compression to remove the highs and maybe a tube preamp to give some warmth.

Now, I'm not an expert....and I know there are a few on this board that really know their apples in regards to this stuff, so here is the question:

How about plugging a wireless reciever into a tube pre-amp to give it some warmth/added control. Does this make any sense considering that there is already a pre-amp (albeit it a lousy one) built in. Or are there any other suggestions.

And how about some compression to chill out the highs. And if so, any recommendations on approach/products.

Many thanks, and let me know if there is any additional info needed.

-Todd