I've got av Yamaha 667 connected with WD TV Live mediaplayer (latest) on hdmi and optical Now I use them to see movies and listen music (mostly flac). AS - Heco Victa 601 (not very expensive - ~500$ ) Looks like ok, but.. I heard that for music stereo amp should be better. So I looked on A-S500 (all reviews are great and price is fair), I'm also planning buy external DAC (may be CA DacMagic) in 6-12 months But I'm still in doubt - will I hear more or less significant improvement in music with A-S500 on RCA for the first time after RX-V667 on optical? Will A-S500 worth purchase for my setup?