I probably can't answer your question anyway, but before anyone can, isn't some more information needed? WHAT Wadia digital source did you play straight in? WHAT passive preamp did you try? I'm a big passive fan myself, and am trying to sell a CAT SL 1 III in consequence, despite its transparancy having been improved by simplifying the signal path. But with my Accuphase DP-75, it's very clear that no preamp is better than even a very good passive preamp, much less the CAT, which comes in a poor third. If a modern Wadia doesn't sound better to you straight in, my suspicion would be that you've become fond of artifacts, which is okay but no criticism of the straight in option. One more factor to consider: how MUCH digital attenuation did you need? The 800 Wadias allow you to adjust so as to need very little, and maybe your older Wadia required you to use too much.
Preamp or Not to Preamp?
Have very expensive equipment, over $50k invested. But found myself strictly listening to digital on the main system. In the past went direct out with Wadia(about 5 yrs ago before the 800 series), and never had enough explosion of soundstage. Tried passive preamp, and just too week for bass. Want to loosen up some money tied up in the system. Using a Reference 2 line stage by Audio Research. Have the AR 600s mono-blocks, and just go with another Wadia digital out?? I could be saving thousands if I dumped the preamp.