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Beneath the bonnet meanwhile works what marketing dubbed the Bel Canto Ultra-Clock circuit. Like many others who point at it as the root cause for poor digital performance, Stronczer seems highly averse to jitter-based timing errors which occur during digital signal transmission and processing when the 1s and 0s are improperly clocked. Timing errors aren’t restricted to D/A conversion proper (here the precision of the master clock is important) but can be caused by servo currents in the transport interacting with the analog reading diodes, power supply disturbances or the signal path between laser diode and converter including a lengthy digital cable.

To combat jitter, Stronczer embraces upsampling—-the CD-2’s remote allows for 48, 96 and 192kHz—-which isn’t without detractors. Why detractors and how does upsampling differ from oversampling? Despite disagreements among manufacturers, a general definition would say that oversampling is intrinsic to digital filtering to shift aliasing artifacts into higher frequency bands where removal allows for shallower filters with better phase integrity (this link has some tech data on the subject).


In principle, upsampling performs just like oversampling but gets inserted ahead of the latter and unlike oversampling, often runs asynchronous rates. As with Bel Canto’s CD-2, the rationale for upsampling is jitter reduction. According to John Stronczer, parallel word length expansion—the CD-2 works with 24 bits—allows implementation of “a totally transparent volume control“. Even very subdued sounds described by at most 2 or 3 bits expand to 5 or six during upsampled recalculations to improve subsequent processing. The entire subject has its critics and Robert Harley’s “The Complete Guide To High-End Audio” for example refers to marketing bits while Altmann, on www.jitter.de, claims that while upsampling does measurably reduce jitter, the upsampled signal has been fundamentally altered to have timing errors embedded in the music data. Problems of asynchronous upsampling are discussed here for example. But as they say, there’s theory and then there’s experience. Because the CD-2 switches upsampling by remote, anyone can conclude for themselves from the comfort of the couch.

Sound: I predict that the impact of upsampling rates won’t whisk you off the couch as a fundamental alteration of the player’s sonic character. While the differences are subtle indeed, I generally had a preference for 48kHz over 192kHz, finding the latter perhaps cleaner and calmer but also more sterile. I won’t waste time discussing these nuances however and instead describe the CD-2’s core personality. If you’ve shunned digital for hardness, the following might shed some – um, light. One personal demand of good hifi involves being able to enjoy less than pristinely recorded material. While I routinely encounter commandments of “the better the system, the worse the sound of poor recordings”, I’m personally in disagreement. It’d be sad indeed if serious investments into hifi meant that the majority of your software became unlistenable. To me, it’d point at a serious flaw in the system. Often resolution becomes the boogieman and synonymous with analytical. The latter results when detail trades places with musical context which often involves a highlighting of transients. Or, a tonal imbalance where the treble operates as a separate entity finds itself tied to high resolving power. I don’t believe this has anything to do with resolving a broad palette of fine nuances. How does any of it relate to the Bel Canto? A few days ago I listened to the Oxford formation Foals’ first LP [Antidotes, 2008]  with its very interesting Math Pop. Instead of broadband guitar assaults UK band style, Antidote—if I observed it correctly—makes do without a single guitar chord. The instrument becomes compelling rather for its taut rhythms and clear-as-glass melodic interplay. Alas less impressive is the general sonic aesthetic to be sadly more hard as glass. Cymbals and hi hats turned downright despicable when my rather silkier Thiel CS3.7 traded places with the CS 2.4 (the former a perfect example for how more resolution can coincide with less vivisection and more long-term satisfaction).