caleco,
you need to turn up the NAD's volume because it doesn't have enough "gain" to drive the low output from a moving coil cartridge. It would probably be reasonably OK for a moving magnet one. [by the way, there are other threads that explain the technical differences between mc and mm cartridges...do a search]
Most preamps and integrated amps these days don't have the capacity to handle the output from a mc cartridge, although more companies are beginning to do so. If you have a mc cartridge, you really have little choice but to get either a separate phono stage or a preamp that has a good one. Problem is that you might like the general qualities of a preamp but not be so excited about the phono section. Thus, the market for phono stages.
The Goldring Eroica is a nice cartridge, but knowing which phono stage to recommend depends on a number of factors: turntable, amp (NAD in this case), whether you prefer tubes to solid state, and whether you are planning to upgrade any of your components in the forseeable future.
That said, I really don't think you can go wrong with an EAR (you can change the tubes to another brand if you like). I have one as well as a Blue Circle BC-23 (solid state) which I also like. Yes the ARC PH3 is preferred by many. It is more expensive, particularly the newer SE model. Depending on what your system is, the PH3 might be overkill.
With a little more information, we should get this figured out for you! But, before making a purchase, I suggest that if there is good audio dealer near you, that you audition some before making up your mind.
