My dealer said it would take about 5 days to properly warm up and about 12 weeks to properly run in. I found he was right on both counts. After 5 days the very detailed but somewhat clinical presentation changed to very detailed and rich. The effect of the run-in period I find hard to put into words. If this makes any sense, I'd say the change is one of impressive Hi-Fi into impressive music.
So if you think the 552 sound good now you've got , you've got a a real treat in-store.