Preamp or A/V receiver???

Hi. I posted a similar question recently but didn't receive the response I thought I would. I'm wondering if a decent A/V receiver is inferior/superior to a tuner/preamp unit such as the Adcom GTP-500II. I currently use my Onkyo Integra DTR 6.3 home theater receiver as my tuner and preamp. I run my Arcam 8SE hdcd/cd player through the A/V receiver, using GlowPower ZYXT interconnects, to my Adcom GFA-555 amp (200 wpc @ 8 ohms). I use solid Audioquest Hyperlitz speaker cables to connect to my KEF Reference 103/4 tower speakers (4 ohm). To my ears the system sounds excellent, but I can never seem to be satisfied. Because I thought the A/V receiver was likely inferior due to the extra electronics (internal DAC, surround sound components, DTS effects, etc), I purchased a nice Adcom GTP-500II tuner/preamp (with remote) on ebay. Both the Onkyo and the Adcom use gold-plated rca connections, and both offer phono inputs. The Onkyo Integra is Malasyian made (surprisingly), while the Adcom is of course a US product. I haven't received the Adcom preamp yet, but I'm wondering if I made the right decision. Any thoughts??