I've used the BBE Sonic Maximizer and currently have a DBX Enhancer. In past years they made a big difference. Theoretically they "put back" what is lost through the electronics in the p.a. system. Lately I am not using one and don't really see the need for it with today's digital gear. Everything seems clean and "alive" without it. You would have to try one to see if it helps in your situation.
I'm doing as many 3 and 4 gigs a day and have tried to eliminate everything that is not essential, without compromising the sound. My gear consists of keyboard, Mackie 1202 VLZ mizer, Peavey digital power amp and DJS1000 speaker system (small sub-bass and satellites). All e.q. and effects from the keyboard.
I suppose in a sit-down situation I would use the enhancer just because I have it.
Mic preamps can indeed improve the sound of your vocals, but as I recall, your voice doesn't need much improvement. Again, the best thing would be to try one and experiment. See if it's worth the $$$$$$ to you.
Are you stil using that worn-out X1?
DonM
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DonM