well that is easy. Anytime I have changed receivers or separates the sound of my setup changes. It becomes a frustrating game trying to find the right combination and sound. I know the audiophiles out there will argue that all power amps should sound the same - but they simply do not. Grab an old Carver TFM power amp, then try something like a NAD or Outlaw, you will hear a noticeable difference. As for receivers, they have so much processing going on none will ever sound the same. This is a very touchy topic for some.