what will make the greatest differance in sound.

The least expensive upgrade is the cables. I agree with the preamp comments.

Monster cables are the weekest link. You can sell the cables and get cheaper ones and still benefit in performance or just leave as is for less. In most of my cases I'm trying to stay as newtral(lo-reactance) as possible choosing interconnects and speaker cables. To me there are very few brands: Cardas, VanDenHul and AudioQuest that are worth paying attention even for the most cheap models. Among these three VanDenHul(if proper research is made) offers the most performance over a buck spent.

I also believe that source have to be the strongest link. The one I would recommend is EMC1

I would suggest:
1) cables first
2) pre second - if you liked tubes, you should probably give serious thought to a good tube pre and/or the Audio Aero Cd player
3) source last - Levinson 390s is quite good, but I personally do not like the 390-380-336 combo - I find it quite fatiguing - so I would break it up either at source or pre... I have found Levinson dealers are usually great about home demos, so (if possible) you should consider a home audition of the full set... and see if you don't feel tired relatively quickly too...

Good luck,
Jacob

Several other considerations:
1. The listening room - are the acoustics of the rooms well suited to the speakers and their placement? Minor changes can yield excellent results.

2. Do you have a dedicated electrical circuit? Again, for small dollars, this will provide good results.

After these two things, many of the above recommendations have merit.

Happy listening, Joel

I owned the Prodigy's and loved them with tubed gear. I had them hooked to a Mac MC2000 and a Hovland preamp. I used Alpha Core Goerts M12 Veracity speaker cables (very inexpensive & good)and had a mix of IC's. My CD player was a Sony SCD-1, which is also quite good, feeding a Dodson DA217MKIID for redbooks. The combo worked quite well and was very musical, & with quality recordings, magical. The new Mac MC 2102 tubed amp is quite reasonable, especially used. See if you can get a dealer in your area to let you audition a good tubed amp & preamp combo, especially if you find the Prodigy's a bit dry. With the right gear, the Prodigy's are terrific.