Loss of inner detail

Greetings,
I've owned a Sony SCD-XA5400ES for 2 years now and really do love it. In my system it has out performed these CDPs:
Electrocompanient EMC-1UP
Linn Ikemi
Meridian 508.24
Accuphase DP-57
Resolution Audio Opus 21
Ayre CX-7e
Bel Canto CD-1

I got the OK from my wife to buy a "final" Transport - DAC (ie: spend a larger dollar amount, ha) that will give me the flexibility of having digital input for the possibility of adding a server at one point.

As I live in Minneapolis I thought I'd try the Bel Canto CD-2 and DAC 3 combo (used). Well, I got a good deal on a used DAC 3 and ran my Sony into the DAC using RCA spdif from the Sony into the DAC3. (I'm waiting to buy a used CD2, but they don't come up often)
ALL inner detail of songs has disappeared (I'm exaggerating a bit, but the difference is quite stark!). Music sounds FAR superior just using the Sony. Why is this?

I'm using a Black Cat Veloce digital cable.

Rest of my system:

Gamut CD-2r preamp
TAD-60 amp
Spendor S9 speakers
Analysis Plus interconnects and speaker cables

Please offer your thoughts as this is my first foray into a separate Transport & DAC

Thanks!