What is your budget? There are a number of alternatives but it depends on how much you want to / can spend.
A couple of weeks back I upgraded my AV system, based on a Denon 1908 AV receiver, with a NAD C356BEE and noticed what I hoped for - significant increase in sound quality, especially in the low-end but also in the treble. I also auditioned the Marantz PM7004 which I was close to buying, but I felt the NAD just suited my sound preference a little better. Also, I listened to the CA 740 which was better at detail delivery (Piano in Kanye West's - Head em say for example) but again I thought to my ears the NAD has more power and rythym. So, those are my proposals. Have a listen to them if you get the chance, to see what you think. Have fun.