matthewpiano said:
The test question is are you still thoroughly enjoying your music?
Spending lots of money on an upgrade won't necessarily bring you any more enjoyment or result in better sound. You have a good system so if you are still loving your music, I'd spend money on more music and carry on enjoying your hi-fi as it is.
+1
Having upgraded from a Cambridge 640a amp & Ruark Epilogue II speakers, I fully concur with Matthew's comments. Having been to the Bristol Show a couple of times and heard a cross section of the 'best' hifi available, I often think that the sound my old system produced regularly outclassed the brash ear-piercing sounds of so-called high-end hifi.
With a separates system, by all means add extra sources that increase functionality, but be very careful indeed before upgrading you main amp & speaker combo, particularly if you like its balance of sound. More money really doesn't always equate to a 'better' sound. It can, but it's not a given: and upgradeitis can be a deep money-pit indeed.
For the money I think the 640a was a superb amp that could handle speakers well above its own budget price range. Its bass control was excellent for a 65 wpc amp: beautifully taut and fast. The 640C CD player could be a little harsh and unforgiving, but when I used other sources (like Bluray) or TV broadcasts, the amp really shone.
Can I ask, do you have a DAC in between your Sonos Connect, Apple TV and the amp? You may find this could improve the quality of your sources. I've not heard it myself, but I understand that the Sonos Connect's own DAC isn't of the highest order.