On the left, on top of the S7i you can see the Wadia 121 DAC. This is an early non-production sample of this new device. It offers all kinds of goodies, such as asynchronous USB input, clocklink input (wordclock compatible), Wadia DigiMaster filtering, digital volume control, and much more, at a very low price. Also: it has very good sound, sounding like a real Wadia, with a well-defined soundstage and excellent focus. Once the production sample is ready, I will post an extensive review.
USB input
The Wadia S7i offers a USB input and this works well. The S7i is immediately recognised by the Macbook and plays without hickups. The sound however isn't on par with its CD replay by quite a large margin: although the bass is nice and tight and the whole is balanced and well-focused. the impression is of a business-likeness, and quite obvious is the Macbook-typical thinness, a certain flatness and lack of color, drive and substance. That this isn't entirely to be blamed on the Macbook was revealed by connecting the Macbook to the PWD MKII's USB input, which resulted in a sound much closer to the Wadia S7i's native CD-playing capabilities in terms of soundstaging, fulness, color and sheer enthusiasm. Michael from Audiac informed me that the USB input on the S7i is indeed synchronous only. The USB input is useful and sounds more or less on par with USB inputs on other DACS. It's just that I've been spoiled with the amazing USB sound on the PS Audio PWD.
S7i DAC with other CD transports
Used as a DAC, fed by a Meridian 506.24, Marantz CD11LE or Levinson 390S cd player, the S7i still recognisibly sounds a lot like itself, but with more smoothness and fluidity, which is normally welcome, but these players also detract from the S7i's normal strong suits, such as dynamics, bass heft and natural midrange. Perhaps if a Philips CD-Pro was used inside the S7i... perhaps that would've been interesting...;-)
S7i Transport capabilities
The Wadia S7i's transport has been optimized for accurate playback and it shows. Using the S7i as a transport only into various DACs, it performs in a consistently tight, fast, dynamic and lively manner. Comparing to the Marantz CD11LE or Levinson 390S as transports, the latter two have more color and a smoother, more relaxed presentation that I favour. But in terms of quality this is a matter of taste. The S7i functions well as a transport and as a DAC, but still, I prefer that S7i playing CD's in an integral manner. This way it just sounds most involving.
Optimisations
The Wadia S7i's dynamic and lively character makes it possible to use the player with wamer powercables and it has no problem being connected to a position more towards the back of the extensionblock. Likewise, interlinks may be the smoother type, although you won't want to go overboard, smoothing over the S7i's strong sides. Setup may work on various racks: the Spider rack may even be a little bit too neutral and I suspect that a weightier rack might work better.
The Wadia 861's full tonality and especially its weighty bass can quickly turn to a thunderous, mushy mess if the player is setup incorrectly. The 861 doesn't like being seconds in the power extensionblock. First place it demands, and nothing less. Also powercabling is critical: use a Belden and you lose much of the colour that it is capable of, use a Harmonic Technology and you're presented with a creamy same-ness with little dynamic differentiation. Thus far for my setup the best powercord for the Wadia 861 is a Lapp, with IeGO 8085 24k Gold connectors. Interlinks may be the fast and open type, but I prefered Transparent Ultra for their smooth, fluid treble yet articulate and fast character, combined with a full tonality. The 861 never sounded better than on a Spider rack, top level. This makes the bass more nimble and articulate and also gets the maximum from the otherwise slightly dark treble. I'd say that if you buy an 861, you owe it to yourself to also get a Spider rack. They're still around second hand, at good prices too.
Relative conclusions
Wadia 861
Best for timbre, color and organic reality in the midrange, best for easy listening.
Wadia S7i
Best for rhythm-driven music, best for detail and openness. An exciting listen.
PS Audio PWD
Best if you want Wadia sound from a streamer. Best in terms of bass solidity and timing as well as for soundstage size and layering.
Overall Wadia S7i conclusion
The S7i is a genuine Wadia, despite the CD Rom transport. I have to say that this is quite an achievement, as I always thought that the VRDS transport was largely responsible for the characteristic robust Wadia sound. Turns out that it is slightly, but only in terms of bass fulness, and perhaps midrange color. The Wadia-typical bass-robustness, drive and power, is all present in the S7i. Another good thing about the S7i is that it doesn't have to warm up each time when you haven't played a cd for a while. Once warmed up, it is ready to rock. The best thing about the S7i is that it has the best treble for a Wadia product yet. It is open and detailed yet never agressive. It can be dry however, but this can easily be combatted with the right setup and cabling. Unlike the Wadia 861, the S7i is much easier to implement in various systems and it is my estimation that many people may find this model more to their liking than earlier Wadias.