Cambridge Audio Azur 851 Series REVIEW

Cambridge Audio Azur 851C CD Player/Preamp/DAC $2499

Cambridge Audio Azur 851A Integrated Amplifier $2799

5 stars

Ashley Kramer may have just found his products of the year with this champion duo from Cambridge Audio

THERE’S SOMETHING SPECIAL about reviewing the latest incarnation of any audio manufacturer’s flagship gear. In theory, the irresistible march of progress means that you’re hearing the very best equipment that the company has ever released (unless the ball has been seriously dropped, that is).

I’ve heard a fair stack of CA components over the years and have never been disappointed – not all of them were five star products but in every case, the value for money was unquestionable. So when it comes to its new top of the table 851 series amplifier and CD player, I wasn’t too worried about poor performance compared to the previous range-toppers. Still, given my previous experience with CA gear, they’re both going to have to perform like champions to maintain the perception of great bang for the bucks.

Azur 851C CD Player/Preamp/DAC

Looking at the two units separately, let’s start with the CD player. Unpacking the 851C tells the user a lot about the product. First of all, it’s nicely packaged with CA’s traditional blue cloth cover and thick chunks of foam to protect it. Even the box shows a degree of ingenuity – as someone who’s lugged a great many boxes of audio gear around, I wholeheartedly approve of the rugged cut-outs on the side of the box that are offset front and back, making the boxes easy to shift – a small detail, but it shows that someone at CA has their head screwed on straight.

The 851C weighs in at a stiff 10kg, which speaks volumes about the solid build quality. There are more inputs and outputs around the back of this thing than there are on many amps, which gives a fair idea of its capabilities. The 851C has a deep feature set, which is heartening for someone like me, who’s loudly declared that he’ll never buy another CD player in his life. This unit is more than just a CD player with 24bit/384kHz upsampling and balanced outputs, it’s also a 24bit/192kHz capable DAC with USB, coaxial, toslink and balanced inputs. In addition, it can serve as a digital preamplifier that can be connected directly to a power amplifier.

That’s a lot of functionality and versatility crammed into one chassis. According to CA, said chassis has new levels of damping and resonance control, and it’s true – this thing is a rock. It’s a good-looking package too, especially in the silver finish. The black vents on the top panel make for an eye-catching effect and match the vents on the top of the amp.

The back of the 851C

Technically speaking, CA has implemented two Analog Devices AD1955 24-bit DACs in a fully balanced dual differential configuration, where each channel has its own DAC and separate analogue filters. The upsampler is Anagram Technologies’ ATF2 system. There’s a big toroidal transformer and a highly specified power supply with totally independent regulation for the transport and the digital and analogue parts of the player. CA has implemented a custom CD servo mechanism and a dampened CD-only transport – there are no cheap DVD drives here, thank you very much.

For the real tweakers out there, the 851C offers the three filter options found on the CA DACs in recent years. These filters are selectable from the remote and the player will recall a different filter for the various digital inputs or the CD transport.

The menu system allows some degree of control and customisation of the 851C: inputs can be renamed, auto play and auto off settings can be changed, the digital volume control activated, the front IR receiver disabled, the USB type altered and the channel balance can be set.

The 851C comes with one of CA’s system remotes, which will control the matching 851A amplifier as well. There are RS232, IR emitter and Control Bus inputs on the back to make for easy integration into a smart installation.

Cambridge Audio Azur 851A Integrated Amplifier

Like the 851C, the 851A is a well put-together piece of kit. Hauling it out of its box, it felt much heavier than the claimed 15Kg weight, possibly because the new chassis is so damn solid. My standard “thump the lid” test revealed that the top panel is well damped, but more thumping and prodding revealed that the rest of the chassis is just as unyielding, especially the side panels, which are almost as resonance free as a chopping board. This is a magical feat at this price point, and there are any number of amplifiers with much higher price tags that ring like bells when subjected to the same test, so kudos to the CA engineers for making such a noticeable effort in this area.

Those very same engineers have crammed a remarkable feature set into that chassis. The spec sheet would make a lot more sense if the price tag were substantially higher. Try this lot on for size:

A huge toroidal transformer is used to supply the power amp stage, while a smaller, completely isolated secondary toroidal is used to feed the preamp stage. Further to this, there are separate transformer taps for the left and right channels, with twin rectifiers and separate PSUs to give dual mono operation of the left and right power amps.

There’s a new balanced silicon gate based volume control giving control in 1dB steps to replace the relay based model used in earlier 8 series amps. The 851A has no less than eight RCA inputs, two of which are balanced (although the balanced inputs can also have single ended sources connected to them, so that’s basically ten inputs). The 851A also offers defeatable tone controls, preamp outs, record in and outs and a full suite of protection circuitry that monitors clipping, current and voltage overloads, short-circuits and temperature. The front panel display is customisable, so each of the inputs can be named and their levels preset. In addition, there’s a 6.35mm headphone output, and there are RS232, IR emitter and Control Bus inputs on the back just like the 851C for home automation integration.

That’s pretty impressive but it doesn’t stop there – the 851A generates a very respectable 120W into 8 Ohms and 200W into 4 Ohms (it measures quite a bit stouter than that according to the Hi-Fi News review). There are substantial extruded heatsinks to disperse any heat, but the 851A should run quite cool considering that it uses CA’s Class XD, technology, which has been a feature of the 8 series amps since they were released. CA claims that it offers the “best of both worlds from Class A and Class A/B amplifier operation.”

The back of the 851A

Skip the extract below from the CA website if you’re not into the technical side of things, but suffice to say, Class XD doesn’t try to eliminate crossover distortion in the way that Class A does; rather, it tries to move or displace it to a non-critical area of the signal’s waveform, which is why CA calls it “Crossover displacement” or XD.

Class XD gives the benefits of pure Class A operation at low levels and eliminates the distortion associated with conventional Class B operation as the fragile audio signal passes though the zero crossing point from transistor to transistor. Distinct from Class AB, XD technology feeds a controlled current into the output stage in such a way that the usual Class B crossover points no longer occur either side of zero volume – the worst possible position in terms of distortion – but displaced to a point where the transfer functions of the transistors are better matched, at a significant output level where it is less audible. The system operates outside of the feedback loop so is not directly involved in the signal amplification itself. The result is a smooth and linear transition between the two key operating modes, Class A and B.

851C Sound Quality

First I set up the 851C in my own system, replacing the Marantz SA8260 that I’ve had for ages. The system is made up of Theophany M5 Series 2 speakers, Viganoni and Viganoni Sachem monoblock power amps and at this stage of the game, Rogue Audio Metis Magnum valve and StereoKnight Silverstone Balance passive preamps. Cabling was a mix of Slinkylinks, Monster, Nordost and Transparent.

I’ve kept the Marantz for so long because I love the way it sounds and I haven’t managed to find anything I like more in my price range. There’s also that reluctance to buy another CD player, but as soon as I heard the 851C, I knew that in some ways it had a slight edge over the SA8260.

Listening closely to Radiohead’s mournful ‘Bullet Proof’ from the Deconstructed compilation CD that I’ve spun more times than I can recall, I noticed that there was more detail on offer than I get with the Marantz. Thom Yorke’s vocals were even more haunting than usual and the sound of the cymbals was both more distinct and more delicate. There was also more separation between the instruments and a greater degree of air and space to the whole performance, which really suited the fragile nature of this song.

The next track on the CD is Badly Drawn Boy’s ‘Silent Sigh’, which isn’t the best recording on the disc – the vocals are a little thin but with the 851C in place, I could hear slightly more of the instruments; the harmony vocals were also clearer. In fact, the 851C managed to open up whatever I played a touch more than I was used to hearing from the Marantz. This was especially notable at the top, which was defined, sibilance free and not at all bright or fatiguing.

On the downside, the Marantz’s bass performance was marginally ahead of the 851C in terms of weight if not in detail – the CA player presented more information as to the exact nature of the bass instruments. The Marantz was still the more exciting player though, which is a characteristic I’ve noted over the years with Marantz players – they’re rhythm kings that get down and boogie with enthusiastic fervor. The 851C was a little more demure and laid back in its presentation but it’s definitely not a stoned hippie, it’s just that the SA8260 is really strong in this area.

Besides the 851’s obvious extra detail, the difference between the two players was subtle and I could easily live with either one. I love a highly detailed sound as much as I prize musical excitement and punch but I also deeply appreciate the way the 851C laid out the minute harmonics and textural differences that are hidden in vocals and instruments. With a good set of speakers and amplification that can reproduce what the 851C is feeding them, all these layers are quite lovely to hear. So in short, if I had to pick one at gunpoint, I’d grab the 851C. That’s not what I said back in May 2007, when I borrowed CA’s 840C, the first of the 8 series CD players. At that stage, the Marantz was my choice, so CA has made real progress over the years.

The differences may be subtle as far as disc spinning goes but when it comes to the other aspects of the 851C’s performance, well… there’s no competition. The only bloke who can get the SA8260 to play computer files or to accept an input from another digital source is Doctor Manhattan, and I’m not sure that even he could get the Marantz to function as a digital preamp. That just shows how far we’ve come in a few years – once upon a time a CD player played CDs, but that’s just not good enough any longer.

Continued on page 2 – click below:


  1. Hi, great review and having just bought the 851A i can only agree with you on the sound and quality – in fact your review convinced me. I noticed the comment on it “should run cool”; in fact it runs really quite hot, so much so that i questioned the dealer on whether this was normal. He referenced this in the manual:

    IMPORTANT – The unit will become hot when in use. Do not stack
    multiple units on top of each other. Do not place in an enclosed area
    such as a bookcase or in a cabinet without sufficient ventilation

    Just for your info.
    Brett Noonan

  2. Thanks for the feedback Brett. I never noticed any major heat coming off the 851A, even after many hours of use but I was running it into some reasonably efficient speakers without spending hours at high volume levels.

  3. Hi Mike,I live in Brazil and have a couple of Marantz reiecvers a 2275 and a 4270. They both have run beautifully for years. But for the last week, the the 4270 has been acting strangely. It started to turn off, and then after a few minutes would turn on again. But last night it turned off and now it won’t turn on. The speaker relay switch is affixed to the inside of the back panel. I have no idea how to remove it for examinationMy situation is complicated by the fact that in this country there is no ready supply (even by mail) of parts. International mail is very expensive and unreliable.I would much appreciate any advice. Kind regards.

Leave a Reply

Your email address will not be published.

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Give a little to support Witchdoctor's quest to save high quality independent journalism. It's easy and painless! Just donate $5 or $10 to our PressPatron account by clicking on the button below.

Witchdoctor straight to your inbox every 2nd week


Advance Paris - Designed with French flair. Amplifiers, Streamers, CD players and more
Previous Story

Castle Compact 5.1 Home Theatre Loudspeaker System REVIEW

Next Story

Pro-Ject Debut Carbon Turntable REVIEW

Latest from Amplifiers

Go toTop