Quick question: you mentioned that you tested the DAC and amp on the Realizer--but then it seems you only went through the 1/4" HP jack & not the RCAs on the rear. I'm not sure that's a great test of the DAC b/c a significant limiting factor might have been the amp (as, indeed, seems to be the case from your comments).
I am interested in the DAC alone because I am now selling my PS Audio PerfectWave DAC (with Bridge) so I can afford to buy a Realizer and I was wondering how much I might suffer for not having a high-end DAC on the back-end; the PWD should bear at least a family resemblance to your W4S as they have many common roots. I wonder, have you since tried the RCAs vs. your W4S? My thinking was that the loss from having an external DAC would be minimal (minimized?) because of Smyth’s bizarre (and terrible) decision to limit the digital out to Toslink… probably the worst digital I/O there is, after HDMI, which they have (again, bizarrely) decided to offer as the only digital input.
NOTE: I am not dumping on the Realizer, per se, after a 2-hour audition at their SoCal HQ, I was sufficiently convinced that I went home and sold my speakers (PMC AML1s) and am selling my DAC, both of which I loved, but I am just pointing out that Smyth could have made much, much better decisions, both in terms of SQ and convenience.
Finally, in response to a note you posed a few pages back, I actually don’t think that the Realizer is at all wasted when used in 2C—in fact, almost my whole audition was done in stereo and I plan on using the Realizer in 2.0 (or 2.1/.2) the majority of my time, once I buy it. Simply put, I would never have considered replacing my 2C rig with a headphone system had the Realizer not existed. Period. But, because it does, and because I rent (and thus have noise/space/room treatment issues that can never be fully addressed or resolved), the Realizer (+ STAX and KGSS) was a no-brainer for me. (That said, multichannel sounds very impressive too, I'm not knocking it.)