I love Avantegarde Trio Omegas too BUT why are you using a 2500 watt amplifier with a 19ohm 110db horn speaker?
Your system makes no sense whatsoever! You should check out a couple of low power push-pull or SET tube amps [300B,845 triode etc. 30 watts max] Same goes for your preamp, all though Burmester is a nice sounding one. It may take some work to get them quite as those speakers are so sensitive. As far as uncolored sound goes, their is no such thing as ALL musical instruments have color and distortion, it's what gives them their distinct sound! I also know a cable designer manufacturer here in the SF Bay Area that has products that are a fraction of the price of those power cables that will totally out perform them! Sorry to say but high price just means your getting ripped off. If you don't know how the those cables are made from an engineering standpoint you should NEVER spend that kind of money. However since funds are not an issue for you check out some tube amps and start listening to music that is color full! You can spend the extra money use saved on a turntable and an open reel tape deck.
Happy listening to those awesome horns.
Vinly9