Hi. Will I make full potential of my upgrade if I partner the marantz cd6002 to my onkyo 606 receiver? The sound of the sony cd player is just ok for me but with this upgrade will I notice a much improve sound quality? Thanks.
I'd say you will probably get an improvement, but won't get the full benefit of the Marantz CD player.
The Marantz is a decent player, and could be partnered with a decent stereo amp. I don't think the Onkyo is anywhere near as good for music as a decent stereo amp, (I have demod a 605).