Cambridge Audio Azur 840C CD Player Review

The CD player is on the way to becoming a relic.

Just as several rather nice sounding players are hitting the market, online music is exploding at a rate that will leave discs in its digital dust. All one has to do is go to any local CD store, IF it’s still open or not fully converted to a multimedia outlet, and see the rows of retail space being given over to DVD’s and games. I sense I am of the last generation of dedicated CD player owners. You might not think that this is a fitting way to open a review of a cdp, especially one I rather enjoy. Actually, this is the most precisely correct way to open this review, given the fact that this player is one of very few which is designed to survive the demise of the age of Disc.

Someone at Cambridge Audio has seen the future and is setting the company up for weathering the huge downturn which is bound to happen when the market for CD players dries up in the next several years. There will be blood in the streets for most traditional manufacturers of cdp’s as they will awaken to discover that they no longer have a generation beholden to CD and the market for their players contracts sharply. In not so many years, a disc-playing device which cannot integrate with online sources will be considered archaic. In tech-savvy circles, that point has already been reached.

The Azur 840C from Cambridge Audio is one of a very few players which will be largely immune to this downturn. In one very real sense, it is as important as a Digital to Analogue Converter and transport as it is a CD player! As a player, it is outstanding; the reports regarding performance past its price point, challenging players in the $4-5k range, are absolutely true. I despaired that a sonically pleasing alternative would be difficult to come by. I should not have worried. The DSP treatment of the disc by the Azur 840C produces a far more refined presentation than the Rega Saturn, my previous reference of the class. Sometimes it takes no more than five minutes to hear the future. In the case of the Azur, it was on the order of one minute; the spaciousness, filigreed layering of details, sparkling treble – it all pointed to an upscale presentation which convinced me the Azur is a player of a particular pedigree which does not come along every day.

Matthew Bramble, the Technical Director of Cambridge Audio, wrote an informative introduction in the manual to the 840C which highlights the virtues bestowed on this player. It is obvious from the design of the unit with its fully balanced layout, twin Analog Devices AD1955 24 bit DACs, true balanced XLR outs, use of DSP processing to up-convert the signal to 24bit/384kHz and a robust casing that Cambridge is out to knock off some competition perched precariously several rungs up the ladder! I have not seen a finer built and sounding cdp in this price range. Frankly, I’ve seen a few more costly players which seem somewhat chintzy in comparison.

Functionally, this is one of the most solid, dependable players I have ever used. It has a fit and finish reminiscent of a Toyota or Nissan. The drawer has heft, the case has heft, it initializes speedily and moves to and from digital input mode efficiently. I have used this unit daily for months and it has never skipped a beat, something which cannot be said of all players today.

I enjoy simplicity in design and function, both of which are evident in the form of the Azur. Its powdered aluminum charcoal façade and simple array of buttons attend the demur but technically inclined central display. It is an unassuming design, one which will not garnish gawking looks, but rather admiring glances when the sound is heard. The most needed functions from the remote are found on the front panel; besides POWER, MENU, and OPEN/CLOSE, PLAY/PAUSE, STOP and SKIP functions, there is the critically important “SELECT” function button. This sets the Azur apart from the bulk of players in its price range as they have no alternative mode to select.

The unit has an array of connections on its backside; RS232C and Control Bus inputs, Coaxial and Toslink digital outputs as well as two sets of similar inputs, a set each of single-ended and balanced outputs. The unit is switchable between 115v and 230v, and has a detachable IEC. The audiophile is truly ready to configure this player to suit whatever technological interests he has.

The Cambridge Audio system remote included is ergonomically efficient and the positioning of the controls is as intuitive. All the main functions of the front panel controls are found on it, including the precious SELECT button. The only quibble with the appearance and functionality of the unit are the gray numerals against the smokey white display background. I found it difficult to read some of the worded information on the display from a distance even when wearing glasses, though the track and time numeration was large enough. A display with more contrast would be welcome.

The Azur can accept two digital inputs, which the SELECT button toggles. For a player in the sub $2k category, the Cambridge has an impressive array of capabilities. Either of the nameable digital inputs are automatically upconverted to the standard output of 24bit/384kHz. Conversely, the internal DAC can be shut off and the digital signal output as raw data with no processing – this is called “Pass Through” mode, which we will return to momentarily.

Purists who shun upsampling will have a fit over use of DSP in this player! Phooey on that; I like it! I normally do not advocate signal fluffing and would cringe at the thought of a two-channel signal subjected to undue manipulation. However, this is different. Instead of extrapolating the two-channel signal and splaying it into a surround mode, the power of processing is being employed in service of the two-channel sound.

The process developed by Cambridge, along with Anagram Technologies of Switzerland, is called “Adaptive Time Filtering”. It is said to “intelligently interpolate” 16bit/44.1kHz (and other) data rates to the ideal. What precisely is happening during this “interpolation”? Matthew Bramble, Technical Director of Cambridge Audio, shed light on this with laser like precision:

“In very simple terms the process is to add extra audio data points between the existing ones. The 32 bit DSP is able to easily generate these points on a 24 bit scale allowing it to fit them between the original 16 bit ones.”

In other words, it makes lots of itty-bitty little bits to be placed in between the bigger itty-bitty bits (I dare you to say that three times fast!). (…and you’ll sound like Twiki. –Ed)

Using a very crude example, if one had to drive their vehicle at 60mph over railroad ties spaced ten feet apart at varying heights from 1” to 3”, the ride would be rough. However, if the average of the height was taken and ties placed every foot forming a smooth curvature of transition between the originals, the ride would become much smoother. Imagine the rough 16-bit points with a myriad of smoothing data points in between to create 24-bit playback. Possibly you can visualize what the difference is – a difference that is easily discerned by the ear.

In addition, crank up the speed of the car to 120mph. Now you’re flying over the not so rough terrain and the once rough going has been made even smoother. John says that jacking up the sampling rate to 384kHz, “…allows a filter with a much (more) gentle roll-off characteristic. This in turn allows a minimum phase topology…” Continuing with our car analogy, the faster a vehicle runs on a smoother course, the less the shock absorbers will have to handle the jarring bumps. Since the data points are added along with increased speed, the “shock absorbing” filters can be streamlined. The extrapolated data points added to the signal achieve a much richer result than can be achieved without the DSP.

This goes beyond simply retrieving existing information to the point of creating additional information! None of this would be possible in an older design. Data is the key; not just how it is treated but how much. More data is almost universally preferential, and the Azur makes so much of it that a lot of it is discarded. One of the wonderful realities of the convergence of computer and component is the emergence of players which can on the fly improve the data Redbook playback! When it is done well the effect is captivating.

Commenting on the smoothness, Matthew enthuses that it, “…manifests itself as a more stable and expansive stereo image.” Indeed, this expansive stereo image is quite different than standard disc players. There is absolutely more “air” but of a different nature than that heard from a recording, for instance the spaciousness of a large hall. It’s a digitally produced air, an openness which just isn’t heard with most players. At times I have described that expanded soundstage as exploded or atomized. The key, however, is that there has not been loss of detail from the expansion, although some might hear it as loss of solidity or density of the music. One can easily hear so much more as a result of it than from most $2k players. Have you ever seen stop-motion video in which camera angles change while the image remains set? In the same way, one almost senses that they can hear not only between but around the notes as they hang in space while the 840C plays.

A decision is in order for audiophiles. Some prefer the hard or solid sound of digital, not in the sense of harshness but of “weight” and density. The Azur does not sound like the traditional cdp with a solid, opaque image. An excellent example of this type of player is the Ayon CD-1, which has remarkably similar detail to the Azur 840C, but with the “solid” sound. The Azur excels at creating an expanded, translucent image of the music. More “illumination” and the 3-D spatial relationships that are so easily gleaned by our senses are generated by the 840C, and for that reason I love it. As a digital color picture engages the senses so much more than a black and white photo, so also the data production of the 840C sparks a wonderful amount of synapse activity in the brain. One might say it’s engaging.

There is one feature on the 840C which stands out above all others in terms of allowing it to provide superb sound. One might be tempted to assume that the upsampled signal is superior to all other forms of operation, an assumption I consider wrong. For a short while after receiving the unit, I was under the impression that the pinnacle of the Azur’s capability was its upsampling playback of CD’s. However, after months of listening to it in every conceivable configuration, I am now convinced that it is most spectacular in the “Pass Through” mode, either as a transport, or through its balanced outputs directly to a preamp or integrated.

Key to this conclusion is the discovery that the “Pass Through” feature yields the most pristine, clean, unadulterated sound possible with the 840C. It must – after all, it is a setting where no peripheral digital processing has been added. There is not a huge difference between the sound of the upsampled signal and that of the “Pass Through” signal. But there is a difference which becomes more evident with higher-end equipment and with use of the balanced outputs. There are two ways to find stunning Redbook playback with the 840C and we shall look at them both, beginning with its use as a transport to an outboard Digital to Analogue Converter (DAC).

Data being exported from the 840C to a DAC can be altered in three ways, by sample frequency, digital word length, and dither. The frequency can be set to 48, 96, or 192kHz. The word width can be set to 16, 20 or 24bit. Finally, dither, as Matthew describes, “…pseudo random noise added to a signal to remove quantization effects which cause harmonic distortion,” can be added. Most pass through CD source material already has dither, so this can be ignored, unless working with an outboard A/D converter. Finessing each of these settings will yield marginal distinctions in sound, but nothing earth-shaking. Most of the differences, say between 16bit, 20bit, and 24bit yielded incremental refinements, fine tuning.

With the player in the “Pass Through” mode, I tried the functionality of the digital outputs with all three variables from bit word length, to sampling frequency, to the “whither dither” option. While there were barely discernable distinctions between each of these treatments of the signal, together they paled in comparison to ability to turn it all off! No matter the treatment of the digital signal (I preferred the 24bit, 96kHz, no dither setting among these options) the absolute clear winner was no treatment of it. Neither the default DSP upsampled 24bit/384kHz result nor the variable results equaled the unbridled signal shot directly untouched to the awaiting Monarchy M24 DAC. After several tests of all the Azur’s distinct output functions, this is clearly a superior way to use it – as a purist transport to a DAC.