"convinced me into buying the Onkyo 905 with HDMI capability" (my Lexicon did not have this).
"AND IT ALL SOUNDS WAY BETTER THAN the original MUCH MORE ELABORATE AND EXPENSIVE system."
One reason the HDMI on the Onkyo ( and/or any other HDMI equipped system ) may sounds better than the digital coax on the Lexicon (or any Digital Coax interface) .... when playing AC3/DTS/or Red Book is ...
The HDMI protocol has a higher data transfer rate than the older digital coax interface has.
Do you remember way back in B.C. (Before Cable) audiophiles preferred recording and listening to their Reel to Reel tapes at 15ips vs 7.5ips (inches per second)