Doug Schroeder details how the

$1,499 Cambridge Audio Azur 840C CD player

is made to survive the demise of the disc

plus new postscript on the 840C's "Pass Through" function

June, 2008

Specifications:

MSRP:  $ 1,499

U.S. Distributor:

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.

The conclusion that the Azur 840C is an excellent player is only half the truth. This machine is outstanding as a transport. The quality of Cambridge’s design for their transport cannot be overemphasized. High quality Mabuchi motors and Sanyo laser blocks were fitted into their own mechanical parts. In fact, the utmost effort to avoid skimping at any point is obvious. The circuit is fully differential, with dual differential AD1955 DACs, differential amplifiers and filters all the way to the XLR outs. There are zero capacitors in the signal path, as it is all DC coupled. A flux toroidal transformer, large electrolytics, all polypropylene caps, and 24 separate regulated power supplies reside inside. A commonality I am seeing in contemporary upscale components is the preponderance of power supplies. Not that it is an infallible guide, but one might get a good indication of build quality by asking one question: How many regulated power supplies are inside? The newer players seem to be dropping them in like candy, and the results are glorious.

Car buyers slam doors. I do, and I assess the sound of the door slamming. Is the seal tight? Does the door carry enough weight when it’s slammed? Does it move smoothly? Millions of data points are calculated as I watch and hear that door close. I also watch and listen to the way a CD tray closes. Does it move in a lurching or gliding fashion? Does the motor sound quiet and refined or noisy? Is there mass to the tray or is it flimsy plastic? While this is not even close to an infallible indicator of quality playback it is a factor. I believe the number of companies which would go to the effort to make a quality transport and put crappy components inside is small. Conversely, not too many manufacturers who work with cheapo transports are going to move decidedly upscale in their topology. With the Azur 840C the evidence is under the hood, and it’s beautiful! This player is as electronically and mechanically pleasing, as it is sonically. That’s not the reason a person buys a player, but it speaks volumes to the passion with which a player is designed and executed.

That’s why in one sense it is a shame that the 840C is best used through bypassing half its internal components!  A waste, you say? Not at all; the “Pass Through” function allows the unit to operate as a transport, while the SELECT function reserves it for a DAC to be used with up to 2 sources! Ah, what genius, what heavenly bliss to this design – two streamlined operations which can serve seemingly irreconcilable sources!  

‘The purists are right; the best sound is when the CD player does nothing to the signal except push it to the DAC, and the Azur sounds like it does absolutely nothing to the signal.’

This player is a study in extremes executed exceptionally well. On the one hand, the player can add data to the hilt, and on the other it can pass along the data adding nothing better than any other cdp transport I have used. One does not realize just how much digital grunge is present in even good CD sound until one hears it removed. If the DSP processing is not wanted, all one needs to do is set the unit to pass along the signal without treatment. The purists are right; the best sound is when the CD player does nothing to the signal except push it to the DAC, and the Azur sounds like it does absolutely nothing to the signal – the epitome of a neutral presentation.. This is a very, very good thing for any outboard DAC as the resultant sound is euphorically clean.

The “Pass Through” function is available for normal playback as well. The Owner’s Manual is a bit confusing as it discusses “raw data” output, as it may lead the audiophile to conclude that a DAC is mandatory for the “Pass Through” feature. However, one can take the signal direct out via “Pass Through” to the pre/integrated of your choice. The resultant sound is the Zenith of the Azur 840C’s capabilities.

SYSTEM

Allow me now to describe the critical distinctions between four listening modes I used operating the 840C. I will begin with the two modes which most closely resemble each other, upsampled CD playback followed by operation as a DAC for a digital source. I will then proceed to discussion of the unit as a transport in the “Pass Through” mode. Finally, I will return to the 840C solely operating in “Pass Through”.  

I primarily used two configurations of associated equipment. Consistent throughout these comparisons were Legacy Focus HD speakers as well as Wire World’s suite of cables comprising Equinox 5 Squared speaker cables, Electra 5 Squared power cords and Gold Starlight Coaxial Digital cable. Amplification was provided by Jeff Rowland’s Capri preamp and 501 mono blocks in the solid-state category, and the Pathos Classic One MkIII tube hybrids in mono mode as tube representatives. These are the two strongest performing rigs in their respective categories. The results of my comparisons between the three modes of operation for the 840C never varied due to the amplification being solid-state or tube. This bodes well for both transistor and tube lovers when it comes to implementing my recommendations for how to use the Azur player.

Also consistent was the use of Wire World’s Equinox 5 Squared interconnects, however one pair was balanced and the other single-ended. This was critical to the discovery that the “Pass Through” mode was superior to all other forms of operation.

To make the distinction between the three modes easier to follow, I will refer only to one disc of the dozens that I tested over the weeks, GRP Gold Encore Series: A Jazz Romance. This disc has some of the loveliest acoustic instrumentals and vocals, as well as one of the most ghastly vocal pieces I can summon to mind! Diane Schuur and Patti Austin are ethereal in their treatment of “Speak Low” and “First Time Love” respectively. Carl Anderson emotes so well on “Pieces of a Heart” that you think he’s lost several of his. But then… what’s with the moaning, groaning “Attack of the Zombies” vocals of Dave Grusin’s “Hurricane Country”? Yikes!

Let’s start with the worst and work our way upward. Grusin’s moribund song (What does moaning like a monster, “YEEaaaah….YEEAAAaaa,” for the better part of an entire song have to do with Hurricanes?) worsened as I moved from regular (upsampled) playback to the upsampled signal sent to the Monarchy M24, to the untouched signal in “Pass Through” mode sent to the Monarchy. It was insufferable in “Pass Through” direct to the amplification!

At first the singing was not so bad, a more nebulous bass warbling with semi-twangy guitar as heard through the normal playback mode. Thankfully, other vocals were enjoyable. A warm glow, relaxed but not the last word in definition type of sound characterizes the upsampled playback. This likely sounds heretical to those who have heard the 840C, as it is tremendously refined sounding to most who hear it in this mode. Carl Anderson’s voice was ever so tight, just a touch piercing. I find that this happens when a player has the “right stuff” but has the wrong cable attached, or perhaps needs a different amp. In this case I was intimately familiar with the amp and cables so I figured that it was the 840C. Sure enough, when I passed the upsampled signal to the Monarchy M24 tube DAC, the strain in his voice, the smudging of the instrumentation cleaned up nicely.

I’m being highly critical here, you must understand. As a teacher might push a student with rare gifts, I am “pushing” the assessment of this player. In stock form it already is superb.

The sampling frequency, as stated above, in this mode is 384kHz. However, when sent to the M24 it fell to 96kHz, which seems to be the Monarchy’s upper limit. Still, the sound was cleaner, deeper in sound field, and more palpable. But there was much better to come in the form of the pristine, absolutely untreated signal sent in “Pass Through” mode to the Monarchy DAC. I was initially surprised to see the Monarchy register “441” on its display, meaning that the incoming signal was sampled at 44.1kHz – the standard Redbook frequency. That made sense, since the 840C processor was now out of the loop. But what was wholly unanticipated was the massive jump in quality in every respect! Depth, intensity, timbre, integration of instruments, flooding and filling of the venue with liveliness – it all came together in this mode.

Consequently the “near death experience” of the hurricane man’s moaning grew ever more unbearable! It was bad enough that he groaned, but now I heard his wretched warbling and low echoes. I was getting some great sound – lousy singing with moaning - but great sound! Carl, on the other hand, sounded much livelier even though his heart was being ripped to pieces. There was no hint whatsoever of tightness in his voice.

But the Zombie Man of the Hurricane was not yet done with me. He was to move from the incorporeal world to the living when I used “Pass Through” with balanced outs right into the Jeff Rowland Capri preamp. This was it, digital playback fleshed out to the finest details. I couldn’t listen, he sounded so dreadful – and that meant the sound was absolutely delightful!

‘The “Pass Through” mode to a refined sounding DAC is the highest expression of what the Azur 840C can do.’

The “Pass Through” mode to a refined sounding DAC is the highest expression of what the Azur 840C can do. So, was it the Digital to Analogue Converter, the Monarchy, responsible for all this?

I thought I would bring the lowbrow champ Oppo 970HD into the rig to find out. If it was everything but the transport that made the most difference, then swapping the Oppo for the Azur should be not so devastating to the sound. But, it was. The Oppo details like crazy, but it was not an authentically high-end sound. Even the well-tempered Monarchy could not keep a lid on the brightness of the Oppo. Everything was brighter and “amped up” sounding, like a gain control had been added and turned up a few notches. The bass was bright and light, the percussion was bright, the voices were bright, etc. There was a complete dropping out of weight and warmth to the bass.  It all reminded me of a hyped car stereo with an in-your-face attitude as opposed to the gracefulness of a fine home rig. Those who would substitute this excellent, economical DVD player for a quality transport are shortchanging themselves. For persons who truly value excellent two-channel playback, money spent on equipment like the Azur 840C is money well spent.

I conducted one other test over the weeks I had the 840C. I used it as a DAC for my Sonos Digital Music System review. Sonos is a hardware and software solution for multiple rooms in one location. It sources its music from either online music services, which are streamed, or one’s NAS (network attached storage). I set up both and used the Azur for the DAC. The convenience was compelling, as all I needed to do in switching sources was utilize the SELECT button on the player.

The 840C was not the absolutely best DAC solution for online sound. The Monarchy, as might be expected, was better at retrieving the best from the streaming audio. However, at no time did the music services or the NAS best CD played back via the “Pass Through” function directly to amplification. In the end, as mightily as I tried, I could not surpass good old Redbook as a source. Did the internet streaming audio through the Monarchy come close enough to reference CD playback to make me eschew the Azur 840C? No, it did not.  It is still a dream to obtain CD quality music from internet sources. It is getting close, very close, but it is not quite there yet. It did not take too much critical listening to find that the Azur is mighty tough to beat.

In the end, the Azur’s upsampled sound was bested, by itself! Put some XLR interconnects on it, set it to “Pass Through” output and you’re done. Done as in no longer looking for the Holy Grail of authentically pleasant digital sound. Done shuffling players. Done with digital glare. Done with effects from jitter. Done lamenting that Redbook will never captivate like vinyl. There is no escaping the excellence of this player; in its “worst” mode it outshines many, but at its best it can be considered a beloved source for rigs $50k and above.

Used in the gloriously uncomplicated “Pass Through” mode, simple acoustic pieces like Ramsey Lewis’ “Sara Jane” (on the same GRP disc) fill marvelously to encompass the entire front of the room. With many sub-$3k CD players, a cluster of acoustic instruments does not entirely cover the stage, but each instrument stays localized. It is an eerily life-like experience to hear the sound waves of an instrument reach across and touch those of another. The cavity which seems to separate instruments in front of the listener as heard through other players simply fills ever so delicately, leaving no void on the stage. One hears a quartet’s instruments not intruding into each other but sonically linking up and synching. In the normal playback and output to external DAC, I did not hear to this extent the holistic relation between instruments. However, it happened direct with the Pass Through mode as the signal was passed through the balanced outputs.

Therefore, I heartily recommend those committed to the Azur 840C to seek preamps and integrateds with balanced (XLR) inputs. The performance of the Azur is marginally better utilizing the balanced outputs versus single-ended, but do not let this stop you if you have only single-ended (RCA) inputs on your pre/integrated! I can’t imagine a poor result in system matching but I can dream of several manufacturers which I long to hear with this player! It is quite possible, since we are speaking of preferences at very refined levels, that you might find a DAC which pairs up well with the 840C to bring your personal Heaven. The fact is you really cannot go wrong with this machine. If you have a CD collection and other digital sources to deal with, you will obtain exceptional results, and I think be most pleased no matter how you utilize it.

LAST TAKE

I had one more chance to determine if an outboard DAC would reverse my opinion on the 840C’s performance as a player versus transport. In this instance, the Van Alstine Ultra Dac had just arrived as I was finalizing this review and would make for a wonderful test for the “Pass Through” discovery. I was surprised to find that it was not suitable for such purposes as it was completely unaffected by the “Pass Through” feature of the 840C! There was no change in sound from the upsampled signal to the untreated signal. Why? The Van Alstine forces the feed from the transport into a true 16 bit parallel processed signal. So, the comparison of upsampled to direct signal was impossible. However, there are many other DACs on the market which can be tried against the Azur 840C’s internals. I guarantee you will have a grand time and experience some very enjoyable audio in the process! I do not, however, guarantee that DACs under $2k will yield better results than the Azur 840C.

With the Azur 840C Cambridge Audio has demonstrated skill in design and manufacturing on several levels – quality per dollar spent, development of technology, introduction of relevant functionality, and tremendously satisfying sound. I enthusiastically endorse this player. It is a truly exciting component because it not only delivers on its stated performance, but goes beyond by allowing the owner to leverage its functionality. With the capacity of the “Pass Through” function it can excel either as a transport or stand alone player. It is a ridiculously good value among components designed for real world audiophiles.

I wonder if Cambridge and Matthew Bond know just how well they have done in creating the 840C? It’s a terrific cdp and a sweet DAC for digital sources. One thing is for sure, the audio community seems largely ignorant of its near reference quality performance in “Pass Through” mode. Now you know it, too.

POSTSCRIPT ON THE 840C'S "PASS THROUGH" FUNCTION

June 11, 2008

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