Phono Pre Amp?


I am using the little NAD but i want to upgrade, I am using a Music Hall MMF5.

What Pre Amp will make an improvement, that costs under $400.00's or is it not even worth upgrading?

Thanks
128x128thegoldenear
If you can stretch your budget a bit, might I suggest checking into the PS Audio GCPH($999 new, $600-700 used and can be modded to good effect latter) It seems to have fallen out of favor here for some reason(not the latest thing maybe?) but it's extremely flexible, priced right, and is dead quiet with great sound quality(at least in my set up) I bought it with the intention of upgrading to a more expensive(BAT,EAR,Ayre)unit but every time I look into this I reach the same conclusion, Nothing's wrong so why spend all that money.
Try Yaqin MS-12B. You can get it at somewhere between $250 and $400. ;-) It worked better than my friend's Bellari with Chinese stock tubes.
I changed the stock 12AX7s to old used mullards and 12AU7s to old RCAs (paid $80 for both), and the sound got much better. It now sounds quite close to my friend's Audio Electronics ae-3 mkii.