We added a EAR MC-4 to our 834P, switched it back to MM and were blown away by the improvement.
The built-in step-up transformers defiantly leave something to be desired, but then again we doubled our cost.
There are lower priced alternatives, see www.10Audio for a DIY step-up.
You might want to try a (lower gain) 5751 at V3. This allowed us to turn our volume control up a little where our preamp sounds better.
Cheers