Only one person mentioned it above, but if you’re moving away from an entry level sound, you need to move on from the entry level amp. Sure the 501 is a great amp to see what things sound like beyond the $300 HTR, but it’s time to move on. A better amp will make those speakers sound better, but I suspect they’ll be next on the chopping block. You’ll have to be prepared to spend more than $800 though. But that’s where you are, and what you want. If you don’t want to spend the money, then just enjoy what you have. Do what I did, I was using an AS-700 and found great deals on a couple of used, well cared for, highly regarded separates. They were $700 and $400 for the pre and power amp, but they were worth it, and I quickly forgot about the Yamaha integrated.