From the Vault

Much gnashing of teeth and wringing of corporate cheque books later, and the B&W Group has become the latest recipient of Philips’ cherished Red Book licence: an exorbitant magic wand that bequeaths the rights to design and assemble own-brand CD players, rather than simply modify an existing box. Incidentally, I hear from trusted sources that manufacturers who have traditionally opted for this cheaper halfway-house will soon be stomped on from a great height. B&W can therefore sleep soundly at night as two variants of a new BitStream player are launched under its ‘Aura’ brandname.

Right on

This is the CD-50, an exceptionally slim player that will set you back some £400 (or £450 for the mirrored, chrome version), and whose elegant appearance will complement Aura’s existing TU-50 tuner and VA-50 amplifier.

With the advent of Philips’ low-slung CDM9 transport mechanism, this could be the first of many sylphlike players, though few manufacturers are likely to buck tradition as confidently as Aura. After all, how many other ‘minimalist’ machines offer a righthand drive?

The player itself is dotted with buttons for play and forward skip, though other facilities, including direct track access, fast search, repeat and program play, have been exiled onto an RD5861 remote handset. The CD-50’s internal logic will not respond to commands for index skipping nor track programming via the IR remote’s 0-9 digit keypad.

The CD-50 was part of a range of electronics released through B&W Group’s Aura brand in the 1990s

Crossing the rubycon

Lift the lid and you’ll discover the guts of the CD-50 come courtesy of Philips’ latter-day 600 series: same master board with its SAA7310 decoder, SAA7321 BitStream DAC and PCF3523 digital output. Same board, that is, except Philips’ LM318 op-amps have been swapped for a pair of OPA2604s, the Burr-Brown ICs popularised by Creek Audio in its CD60 and DAC60 products.

Furthermore, these new op-amps are DC-biased up to +2.5V or so – an attempt to free the chip of crossover distortions – while relying on a pair of Nichicon Muse electrolytics to AC-couple the analogue line outputs. Or so the story goes; after all, our sample was still equipped with Philips’ original Rubycon capacitors...

Lab report

Despite Aura’s modifications, including those to the servo board, the CD-50 is neither slicker in operation nor more impressive on the bench than any previous 600-series player. In fact, the hallmarks of Philips’ CD624/634 remain glaringly obvious, including distortion, which ranges from 0.0015-0.046% at 0dB to a less impressive 0.63-1.9% at –60dB. Once again, the 3D plot betrays the rippled stop-band noise (V-patterns) of Philips’ initial 4x oversampling filter (the compound rate is 256x) while characteristic 3rd and 5th harmonics dominate the distortion spectrum.

This is also true of the dithered –70dB trace, which goes on to expose a CLV tone at 7.35kHz, the same spurious tone that reduces the CD-50’s overall S/N ratio to 96-97dB (A-wtd). Also, the SAA7321’s distinctive 3dB lurch in resolution at –90dB is maintained, as is the low-ish 1.91V output level and 204ohm output impedance of Philips’ original players!

The only appreciable difference that exists between the CD624/634 and Aura’s CD-50 is therefore revealed by the low-level frequency response, the latter player having a ‘warmer’ upper bass and exaggerated 0.35dB filter ripples. This should be sufficient, in my experience, to provoke a subtle change in sound quality.

Smooth operator
As the melancholy pirouette of low whistle and pipes from Christy Moore’s ‘Bright Blue Rose’ wound to a close, I was struck by the conspicuously ‘engineered’ sound of the Aura CD-50. Here is a player that flaunts the traditional signature of Philips’ BitStream system, and the SAA7321 DAC in particular, yet tempers this with a lushness, a warmth and smoothness all its own. Vocals, for example, are gloriously expressive but remain tainted with that steely, insipid quality that’s damnably hard to avoid with this single-ended DAC. Philips’ CD624/634 were no more successful in this regard but they also lacked the thread of compassion that runs through this player.

Plenty of ‘fresh air’ inside the full-width CD-50, where a Philips’ CDM9 disc transport fed into a board featuring the manufacturer’s SAA7310 decoder and SAA7321 BitStream DAC

So the Aura CD-50’s vocal performance is, at best, a little mixed. Any accompanying instruments, meanwhile, typically sound warm and rich in colour, strings are vibrant and full while the entire bass seems flooded with a generous pool of harmonics. Here was a colourful sound but one that’s inevitably contrived.

Clearly there is some invention on the part of Aura’s CD player, but such creativity is no bad thing. It certainly preserves a sense of decorum, maintaining the ambient bass, the driving rhythm and sheer electricity of U2’s ‘Real Thing’ while soothing its raw treble.

Go with the flow

All the power, it would seem, without the pain. Fortunately, this does not strip the gloss from naturally thrilling instruments, strings and piano, for example. There is a subtle loss of freshness from the CD-50, of transparency and in the airiness that might otherwise accompany each key stroke, yet the music as a whole does not appear undynamic or claustrophobic. These are quirks of balance and timbre, foibles that do not prevent Aura’s player from remaining faithful to the tide of feeling within its music.

Indeed, despite this loss of incisive high frequency detail, the CD-50 remains resolutely euphonic in presentation. As a result, the atmosphere, if not the filigree percussion, that saturates the likes of 'Shepherd Moons' still succeeds in flooding across. Individual instruments coalesce into a broad canvas of music rather than existing as a series of disparate cameos, an effect that will find you slipping into the music without straining to hear subtle and generally inconsequential details.

It is the overall performance that really counts and, in this respect at least, the sum total of the CD-50 is rather more impressive than its tried-and-tested ingredients.

The player sold in black (£400) and chrome (£450), and was supplied with RD5861 remote for in-the-hand control of functions including repeat and random play

Conclusion

This player is no cynical renegade from the Philips parts bin, but neither is it a technological triumph. The CD-50 is an unremarkable but polished newcomer, one that is very smooth, comfortable and communicative, a player that conveys the spirit rather than the building blocks of its music. All part of Aura’s grand plan, I am sure: a mellow-sounding player to complement the unforced, though not uncoloured, mien of its amplifiers.

Compared with Arcam’s Alpha Plus or even Rotel’s RCD-965BX LE, Aura’s CD-50 represents a thoroughly congenial alternative, a player that is neither quick off the mark nor especially searching in its presentation. It is, however, obstinately listenable!