What determines the volume of a Turntable?

What determines the volume of a Turntable? Is it the Cartridge? Is it the Phone Pre Amp? Is it the combination of both, if so how do I know which Phono Pre Amp to buy with my Turntable? I purchase a Music Hall MMF5 just to get my feet wet, with an NAD PP120.

Is this a good match up or should I upgrade.

The rest of the systems is as follows.

Primare I21
Primare CD21
Thiel 1.6
Kimber Kable Interconects

Shopping for speaker cable?

Any suggestions would be great on both fronts (phono pre amp and speaker cable).

Thanks

Kevin