Ctsamg, without giving us a budget, this is a guessing game, so bear with me... You have an excellent TT. If we can put the issue of a phono stage aside for a minute, let's look at your cartridge. I encourage you to read this TNT-Audio review:Shure M97xe cartridge
Of course, you should take any review with a grain of salt, but if you sift through this forum, you'll find others who thought the M97xe was dull and lacking:Technics SL1200MK2 Cartridge
My point is that you should seriously consider a different cartridge. You don't have to refinance your house to get something decent. If you read through the above forum, you'll find some excellent suggestions like these: Sumiko PearlAT 150 MLXDenon DL-160Grado Sonata
You should read this testimony from a group of Technics SL1210 owners that have an Audio Technica AT150MLX: I just went up two notches in resolution
Here's another forum worth checking out: denon 160, AT 150, orton 540 mk2 or Grado Sonata?
As for a phono stage, I *strongly* recommend tubes. In my experience, low-cost tube phono preamps always sound more realistic than low-cost solid state phono preamps. The only exception is the Bellari VP129 - avoid it. I haven't heard the Cambridge 640 to be able to comment on it, but I've owned several other SS phono preamps in that price range to know they don't offer three dimensional realism or a lush smooth midrange. If you combine any of the above cartridges with one of the following phono stages, I'll bet you'll be very happy. Jolida JD9Pro-Ject Tube Box
(and Tube Box II)Wright WPP200cWright WPP100cAntique Sound Lab Mini Phono
DIY kits: Bottlehead SeductionHagerman Cornet2