At one time in my life I was doing a lot of recording on a Roland VS-1680, and my biggest issue was mic preamps. An insufficient mic pre amp can make life miserable.
There are a lot of solutions, but I had good luck with a Presonus Eureka (roughly $499 today, although it was more expensive when I first got it). It has a good preamp, compression, EQ, and +48V for phantom-powered mics. I am sure someone can recommend something less expensive, especially if you only need the preamp and phantom power, and not the full channel strip.
I still have it in the rack and use it sometimes. Other times I use the preamps built into the V-Studio.
The main point is that if your preamp does not have enough clean and quiet gain, it will be very difficult to get a good sound. There are a lot of good inexpensive mics but without a good preamp, they won't do well.
http://www.sweetwater.com/store/detail/Eureka