April 2011

Cambridge Azur 650RCambridge Audio, based in the UK, has a long history of building affordable two-channel gear that puts far more costly components to shame. But if affordable is Cambridge’s middle name, it could just as easily be innovative. Take, for one example, the Azur 840A two-channel integrated amplifier -- its power-amp stage is unique in being class-XD, a hybrid of class-A and class-B that promises low levels of distortion. Another is their DAC Magic D/A converter, with its switchable proprietary filter algorithms. 

Although the subject of this review, the Azur 650R A/V receiver, lacks the class-XD amplifier stage and the sophistication of the DAC Magic DAC, Cambridge Audio claims to have paid much attention to its sound quality, and to have successfully combined an audiophile-grade integrated amplifier with most of the modern conveniences a home-theater enthusiast would desire -- all for $1799.99 USD.

Look and feel 

With its solid brushed-aluminum face in classic Cambridge Audio silver, the Azur 650R has an understated handsomeness that’s easy to like. Like most Cambridge models, it’s also available in black, but I think it looks particularly good in silver. I like the fact that there aren’t too many buttons on the front, making it easy to navigate the myriad options offered by this sophisticated component. It measures 16.9”W x 5.9”H x 16.5”D, its compact case belying the fact that it contains seven channels of power amplification. 

Like its faceplate, the 650R’s silvery remote is simple and functional, its supermodel slimness easy to grasp and use. The remote’s buttons have a nice feel, with reassuring tactile feedback. What I like best about the remote is being able to toggle the subwoofer in and out with a single button; its most bothersome aspect is that it’s not backlit -- frustrating for those of us who like to watch movies in complete darkness. 


The Azur 650R’s amplifier section is claimed to output 100Wx7 into 8 ohms, all channels driven. In my listening sessions, it never lacked the power to drive a variety of speakers in my room to very loud levels -- remarkable, given the receiver’s fairly small size. Cambridge Audio’s claim that the 650R’s amp section is “audiophile grade” is at least partly confirmed by the toroidal transformer visible through the top vents. 

Also visible through the top vents, and dominating the middle of the chassis of the 650R’s interior, is what Cambridge calls its X-Tract Forced/Convection Heat tunnel. Used in lieu of massive heatsinks, this tunnel directs heat through the amp’s interior to a vent at the rear. If the tunnel can’t passively dissipate heat quickly enough by convection alone, a small fan on the rear panel kicks in. This system worked well; unlike with some other receivers I’ve used, I could never tell whether the 650R’s fan was operating or not. 

For surround-sound processing and decoding, the Azur 650R has a Cirrus CS49700 chipset with two 32-bit DSP cores. This enables on-the-fly decoding of DTS-HD Master Audio and Dolby TrueHD. Also present is a feature now included in all DTS-HD-capable 7.1-channel receivers, but that I hadn’t seen implemented before: DTS-HD Speaker Remap uses the power of the DSPs to set up virtual speaker locations in seven different configurations, if the surround soundtrack requires them -- a sort of “listen-the-way-the-artist-intended” feature. 


For high-definition video signals, the Azur 650R has three HDMI 1.3C and three component-video inputs, and one each of component and HDMI outputs. There are also tons of standard-definition video inputs and outputs. Though it lacks a name-brand scaler such as ABT or HVQ, the Azur 650R can upscale analog video signals to HDMI. This means you can connect it to your TV with a single HDMI cable. For audio, there are an unusually high number of digital inputs: five coaxial and six optical. There are also 7.1-channel sets of analog inputs and preamp outputs. 

Cambridge Audio equips the Azur 650R with the ability to connect to Incognito, a sophisticated custom-installation setup. Incognito has a host of keypads, hubs, and devices that the 650R can interface with to distribute music and video throughout your house. 

Cambridge Azur 650R

Audiophile alert 

Cambridge Audio has put a lot of thought into the Azur 650R’s audiophile qualities. The digital signal processing (DSP), for example, outputs to separate stereo DACs capable of handling 24-bit/192kHz signals. In the 650R’s analog Stereo Direct mode, analog connections can be played back with no DSP processing. The 650R can play both DVD-Audio and SACD discs, albeit with DSD converted to linear PCM. If you’re running a 5.1-channel setup, you can biamp the front-channel speakers with the rear surround amplification channels, if the speakers are capable of it.

GUI and speaker calibration 

The biggest drawbacks of the Azur 650R are its graphic user interface (GUI) and onscreen display (OSD). A button on the remote labeled I/O brings up the OSD -- not very intuitive. The first menu is displayed in a font that looks like the one used in Microsoft’s original DOS. But to Cambridge Audio’s credit, I found it easy to navigate the menu; there was nothing confusing about configuring the receiver through this OSD. 

Another hiccup occurred when I set up my speakers with the built-in Cambridge Audio Mic Controlled Auto Set-up (CAMCAS): There’s no dedicated port to plug the supplied calibration microphone into. I had to consult the owner’s manual, where I discovered the answer: the left audio RCA input jack. That done, I hit Auto Setup on the menu and jumped three feet in the air -- I was blasted by the loudest pink noise I’ve heard from any setup routine! In my first run through the setup, the 650R detected an error: it told me that the left and rear surround speakers weren’t present. I consulted the owner’s manual again and found that you must state whether you’re running a 5.1-, 6.1-, or 7.1-channel setup. Once I’d done that, setup was completed without a hitch. CAMCAS corrects only for distance and level -- it won’t recommend a crossover frequency. Keeping to Cambridge’s minimalist roots, it won’t correct for any phase or frequency anomalies present in your speaker or influenced by your room. 


Despite my gripes about the Azur 650R’s GUI, once I was done with fiddling with it and had sat down to listen to music, I discovered that it’s one of the best AVRs I’ve heard. What was most impressive was its transparency -- unheard of in most receivers of my experience. When I listen to music through an AVR, there’s normally a veil over the sound that ranges from slight to heavy in terms of how much it obscures subtle details. This was not present at all in the 650R’s sound when I listened to my best recordings, such Patricia Barber’s Nightclub (SACD, Mobile Fidelity Sound Lab UDSACD 2004). Her voice had a she-is-here presence through the 650R that was natural enough to rival integrated amplifiers in its price range. This characteristic was present even though the Azur 650R can’t accept SACD in its natural DSD form, but converts it to linear PCM. Barber’s voice sounded particularly smooth, and the sound of the cymbals came through as naturally detailed, with airy highs that decayed slowly and completely. Again, the sound was smooth through the midrange, which gave a natural warmth to voices, but not so smooth as to make me think that the 650R was manipulating or overprocessing the sound. 

The Azur 650R also excelled in dynamic range. When I listened to Barber’s recording of “Bye Bye Blackbird,” also on Nightclub, the sharp attacks of the piano notes seemed to explode from a dark background of silence. This characteristic was present at almost any volume level I tried, and with all of the different speakers that I used. The best sonic match was Monitor Audio’s Silver RX system, which came to life through the Azur 650R, despite these speakers being fairly demanding of power. 

The dynamic, powerful sound carried over to home-theater use. When listening to demanding soundtracks, such as in the Blu-ray edition of Sherlock Holmes (2009), the Azur 650R performed particularly well. In the opening sequence, as a horse-drawn carriage races through the streets of 19th-century London, the soundtrack uses all five speakers and the subwoofer -- the 650R played it loudly and convincingly, without dynamic compression or distortion. This sequence also showed off the high-frequency smoothness I made such a fuss over during my two-channel listening. In the first few minutes of the scene, when a fight breaks out, the sound is muffled except for some highs best described as sounding like a tuning fork. This sound can be grating through other systems, but not so with the 650R. The effect isn’t supposed to be pleasant; the Cambridge so well straddled the line between smooth and edgy sound that its performance seemed to belong to the realm of separates, not midpriced receivers. 

Even though the Azur 650R lacks a name-brand video scaler or processor, it didn’t detract from the video quality through my Oppo BDP-83. The Cambridge didn’t alter the video signal at all -- something that can’t be said of my mainstay receiver, the Integra DTR-8.8 ($2400, discontinued). Although my Integra receiver includes an HVQ Reon chip for video scaling and processing, its implementation is flawed, significantly altering black levels, an annoyance I didn’t have to deal with using the Cambridge Azur 650R.

Comparing the features of the Cambridge Azur 650R and the Integra DTR-8.8, the Integra holds its own despite being a few years old. The Integra has a lousy GUI, but it still looks a bit better than the 650R’s. Another feature lacking in the 650R is network connectivity for audio files. With the Integra, I can play audio files from a central server or other computers connected to the network. The DTR-8.8 also has a pretty sophisticated automated speaker-setup routine: Audyssey’s MultEQ XT is built in, and not only calculates distance and levels, but also sets crossover frequencies and compensates for phase and frequency response. The 650R will be much more to the liking of those who argue that these features only serve to screw up the sound. The DTR-8.8 will also accept DSD bitstream signals directly from SACDs without converting them to linear PCM -- if you have SACDs, the Integra might better suit you. Other conveniences present in the DTR-8.8 but lacking in the 650R are dual HDMI outputs, four HDMI inputs, a backlit remote, and volume level indicated on the OSD. 

But none of these will be deal-killers for most who consider the sound quality of the Azur 650R, because that’s where it excels -- in pure sound quality. While the Integra DTR-8.8 is fine playing Blu-ray movies, it lacks that extra bit of smoothness and transparency that the Azur 650R could extract from most two-channel recordings. The Integra DTR-8.8 has always left me wondering how much better the sound might be if I added an integrated amp to my setup. With the Cambridge Audio, I doubt you’d ever think of adding separates to your system.


No doubt many of you have gotten used to such modern conveniences as slick OSDs and GUIs, network connectivity, and effortless setup. If that describes you, then Cambridge Audio’s Azur 650R A/V receiver might not suit. However, if you value sound quality above all, and particularly two-channel sound, as much as or more than you value home-theater listening, then you’d be ecstatic with the Azur 650R. It sounds like high-quality two-channel gear, in the best sense. If you mainly listen to music but also want a very capable centerpiece for your home theater, I highly recommend that you audition the Azur 650R. 

. . . Vince Hanada

Associated Equipment 

  • A/V receiver -- Integra DTR-8.8
  • Speakers -- Axiom Audio Epic 80-800, Monitor Audio Silver RX, Definitive Technology Mythos XTR-50
  • Source -- Oppo BDP-83 Blu-ray player
  • Cables -- Analysis Plus Blue Oval in-wall speaker cable, Analysis Plus Super Sub interconnects
  • Monitor -- Sanyo PLV-Z5 front projector

Model: Cambridge Audio Azur 650R
Price: $1799.99 USD.
Warranty: Three years parts and labor. 

Cambridge Audio
Gallery Court, Hankey Place
London SE1 4BB, England, UK
Phone: +44 (0)20-7940-2200 

Website: www.cambridgeaudio.com

North American distributors: 

Audio Plus Services (US)
156 Lawrence Paquette Industrial Dr.
Champlain, NY 12919
Phone: (800) 663-9352

Website: www.audioplusservices.com

Plurison (Canada)
313 Marion St.
Le Gardeur, Quebec J5Z 4W8
Phone: (866) 271-5689

Website: www.plurison.com