Carl,
Whose to say it would be a waste, a better amp is a better amp. Are you asking if it is more important to upgrade the preamp or the amp at this point?
I should also clarify my comments on thinking the 502 is "ok" as a preamp. I purchased the 502/557 combo years ago to replace a Forte combo; I really thought the Forte preamp was going to be the weaker of the Forte combo. With that thinking I put the 557 in my system first and left the Forte (Model 2) preamp to see if there was much difference in the amps, it was huge! The 557 was far better, immediately. I then, the same night, replaced the Forte pre with the 502, I should of waited longer so I could of grasped the differences, it didn't seem major to me. Though it didn't "seem" major to me, I really didn't give a fair head-to-head compare to the Forte.
TAS's newest issue has a review of the 502/559 and they speak well of the 502.
