Cambridge Azur 851A integrated amplifier

The more integrated amps I review, the more I want to tell manufacturers: Please, skip the DAC, omit the phono stage, lose the Bluetooth—just give me the best sound quality, and the most vivid, most transparent line stage and control center (with pre-out) you can design. Make sure this line stage has appropriate gain, and high input and low output impedances. Give me at least four balanced and single-ended inputs. Make sure the volume, balance, and tone controls are durable and degrade the sound as little as possible. That way, I can add a DAC, server, phono stage, or Bluetooth, of any quality level, any time I choose.

Provide a good solid-state amplifier of medium to high power, but don't go crazy with the cost. That way, I can take my time and figure out which speakers I'd like in my room. Then, when everything else is in place, I can choose a different amp—the one that makes the most magic with the speakers I've chosen. In short, I want a cornerstone on which I can build a high-quality high-end system that should retain its usefulness and resale value—and that I should enjoy—for decades to come.

Cambridge Audio's Azur 851A might just be that type of integrated amp.

On their website, Cambridge Audio describes the Azur 851A ($1900) as their "Flagship Integrated Class XD Amplifier," and that it provides "120 watts per channel of Class XD amplification" from "an acoustically damped full metal chassis." Class XD is Cambridge's "proprietary amplifier circuit design," which they say "offers superior sound quality [to that] currently available from existing amplifier configurations. . . .

"Class XD (crossover displacement), 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 through the zero crossing point from transistor to transistor. The result is a smooth and linear transition between the two key operating modes, class-A and -B." (Hallucination publicitaire?)

The Azur 851A's front panel is dominated by an attractive blue display with adjustable brightness. In addition to the tone controls, which can be switched out of the signal path, there are a headphone jack, seven source buttons nameable by the user, a smooth-as-a-kitten volume control, and a Mode button that lets the user shuttle between Volume, Balance, and Program modes. In Program, the gain can be trimmed for each source, which permits the user to bring all inputs up to the level of the highest gain source, or vice versa. What? No Mono button?

The mains switch is on the rear panel, as are two sets of speaker terminals (A and B, selectable via the front panel), an infrared emitter input, an RS232C port for external control in a custom installation, preamp out, and record in and out. For two of the inputs, a choice of RCA or balanced XLR inputs is provided.

I hooked up the Azur 851A, switched it on, and pushed the front-panel button that toggles the amp between Standby to On—which caused the rectangular display to glow a beautiful shade of soft gray-blue. I selected Source 1, and pushed Play on my CD player. It was early afternoon; I was very revved to hear Jean-Yves Thibaudet playing Satie . . .

BOOM! BOOM! Hey!! OMG! What the...? A loud popping sound was followed by the cones of my DeVore Fidelity Orangutan O/93 speakers came jumping out like Miley's tongue. Holy Moley! What have I done? I groped frantically for the Standby switch and stared at that pretty blue display. It was flashing "DC ERROR! DC ERROR!"

Sitting on the floor, hyperventilating, I checked the manual for troubleshooting tips and discovered explanations of the CAP5 Fiveway protection system. I checked all of my connections, including to AC, turned the volume down to –93, and powered up the 851A again, this time using a variac. Everything looked pretty okay, so I turned the volume up a smidge, to –82, and suddenly the volume went full throttle (–00), instigating crashing sounds and insanely pumping cones. Again the 851A flashed "DC ERROR! DC ERROR!" Fearful for my privates, I shut it down again. After a few stressful intimate moments with the Reset button, I called John Bevier at Audio Plus Services, Cambridge Audio's US distributor, who sent me another Azur 851A. It scared me less than the first one—and liked me more.

Life and fire
After a few days of breaking in the second Azur 851A by streaming electronic dance music, I played Japanese Koto Classics (LP, Nonesuch Explorer Series H-72008). The first track, Zangetsu (Lingering Moonlight), was composed in the 18th century and is an offering to a beloved person's spirit. I used the VPI Traveler turntable and tonearm fitted with an Ortofon 2M Black cartridge, and the Soundsmith MMP3 phono stage (footnote 1). Right out of the box, I was having feelings of warmth and excitement about this Cambridge integrated. The koto was enjoyably present, detailed, properly scaled, and sounded very natural.

The starts and stops of notes felt just right—not too soft or hard, not too quick or slow. Crisp and colorful!, I kept thinking, and wondered: Maybe I underestimated how vivid and dynamic the Ortofon 2M Black and Soundsmith MMP3 could be. I can't remember having ever been impressed or excited by the 2M Black's microdynamic expression—and now I was. I was even having flashbacks of the Koetsu Rosewood Signature. I know Japanese Koto Classics from when I actually owned one of Sugano-San's psychedelic Koetsu moving-coils—and now I was enjoying this album in a way I hadn't since then.

On the second cut, Fuki (Riches and Honors), koto master Shinichi Yuize improvises a vocal melody over the ancient koto composition. The Azur 851A let me lock on to and fall into this virtuously poetic musical event. It also made clear that Yuize's koto was roughly 6' long and that the mike was about 3' from it. Color and space everywhere, with more flashy sonics and sinewy transients than I'm used to from my system. Something really good was taking place—either the LP, the Cambridge Azur, or the front end was making some unusually exciting music. I decided to try a CD.

Cheating on Aldo
I am so in love with Aldo Ciccolini's spirited, irony-filled renderings of Eric Satie's piano music that, every time I listen to Ciccolini's student, Jean-Yves Thibaudet, playing these masterpieces of La Belle Epoch, I feel I'm cheating on my girlfriend. But listening to Thibaudet's Satie: The Complete Solo Piano Music (5 CDs, Decca 473 620-2), I also feel I can better grasp those eccentric, weirdly poetic "performance indications" that Satie famously inscribed between the staves: "without pride," "with astonishment," "sadly," "gravely," etc. Thibaudet brings me even closer than Ciccolini to the piquant, melancholy effects called for in Satie's notes, and shows me even more of Satie's moods.

Footnote 1: Michael Fremer reviewed the Soundsmith in Stereophile, October 2011.
Cambridge Audio
US distributor: Audio Plus Services
156 Lawrence Paquette Industrial Drive
Champlain, NY 12919
(800) 663-9352

iosiP's picture

I mean, the first sample did not work, the second had problems in the right channel. And these are samples send to reviewers, not purchased by the unsuspecting customer.
I know they are making them in China but for close to $2k I certainly expect better QC!

Erik's picture

I've been wanting to demo this amp for a while and this didn't change that one bit!

Totally get what you say about texture and color, and from one junkie to another, you should have a look at the Hegel H80. Never mind the built in DAC, the amp gels superbly with the Rega in apodizing mode.

BaTou069's picture

Hello Herb,
Great Review! You mentioned the Rogue Audio Sphinx as Associated Equipment but didn't write a word of comparison. I find this comparison rather interesting, both integrated being fully analog, almost same price range, but different approach. Could you fill in? Thanks's picture

One blew up, one had other major problems. Makes me want to stay away from the whole company. Consumers dont have test gear, we sort of have to hope that things work..... Can you imagine what a hassle the dealer would give you if you tried to return a product saying the right channel sounds distorted? Its great that stereophile can find these faults with measurements, but that does little for the average consumer who just got screwed. Terrible. All cambridge product are off my list

damir's picture

My Cambridge Audio 840C cd player died twice.

First fix cost me 700 USD.

A year later, it failed, the same way it failed the first time!

I gave up on Cambridge Audio, although that DAC was really doing magic while it worked.

Same thing I can say about NAD C370... had two of them bridged... both died the same way.

Right now, I'm on NAD m51 and m3... fingers crossed master series will last longer.

corrective_unconscious's picture

What problem was that exactly that happened twice to the CD player? It was out of warranty and you repaired a $1200 to $1500 component for $700.... What shop or dealer handled the $700 repair? I assume you contacted the same people when it happened the second time...whether out of the repair warranty period or not.

damir's picture

Yes, it was just out of warranty, I paid for the fix. I liked the sound and several digital inputs it offered.

There is a loud noise coming from the left channel when you first turn on the CD player. Turn off, turn on, turn off... let it warm up and after some time the *loud* white noise stops and you can start using it.

They replaced the complete motherboard the first time.

A year later, it happened again. I am not going to spend 700 USD again to fix it.

Cambridge Audio - never again.

corrective_unconscious's picture

It was about a $1200 component, at least two years old, which means depreciated to about $600 or $700, and you spent $700 to get it fixed.

There's a first time for everything. I wouldn't use the phrase "motherboard" for a CD player, personally. What board? A power supply board? A digital chip board? What were the symptoms of this failure? It made funny noises but after warmup you could use it normally?

What dealer did the repair? What did they say when the exact same "motherboard" problem re occurred? Didn't you complain to the dealer and to the manufacturer after the expensive repair failed in the same way? What did they have to say for themselves?

I found a nice image of the guts (C rev.) for us to look at:

mendaily DOT com/wp-content/uploads/2012/12 FORWARD SLASH Cambridge-Audio-Azur-851C-Inside DOT jpg

damir's picture

I don't understand what is confusing you. I did not want to buy a new one, I fixed the old one.

They changed the complete *motherboard* with DAC, CPU's, condensators, external connectors, everything.

What dealer? The one that represents cambridge audio and sells the CD player.

Why would I complain again? What could they say? It lasted for a bit over a year and died just like it did the first time.

I wrote in the previous message, it had loud white noise going on a left channel, until it warmed up.

Here is the photo of the motherboard:

FlyhiG's picture

Your report mirrors my experience with CA products. Great sound nice features but not reliable aa one would expect. Sold by the better stores, so not inexpensive. Just too many other makers for me to take a chance on CA gear again.

mrd745_2000's picture

In many stereophile articles you mention where the product is made. I suggest you mention it for every product. I have had bad luck with made in china products. The manufacturers seem to think this is acceptable since they provide us with a short warranty period. I disagree. This gear cost a lot of money. We should get a reliable product that should last for years. But I have made my choice. If I cannot afford a north american or european product I will buy something used or wait. Manufacturers comments that they monitor quality contol or own the factory are meaningless. No more made in China for me.

Sugarbear66's picture

OK I got mine in 2012 and LOVED it, by 2014 it was randomly turning off and weird volume knob issues. (turning it down turned it up) so I had to use remote but, that was fine. But, the turning off got worse and so 6 weeks of a repair later it came back working great and now it's 2016 I'm sending it back again for repair. I've finally lost patience with it, I love the way it sounds, I love the aesthetics of it, it's a 2k integrated but, I had to break up with it. I Just installed a Rogue Audio Sphinx v2 in my rig to replace it during the 851 repair and it's a dream. Maybe I got a lemon 851a. But, no matter my love for the Cambridge it the quirkiness did me in in the end. Happy with my Rogue.

allhifi's picture

SB66: Good call.

I have a 840E preamp -great piece, but damn the under-spec'd resistor/relay 'volume attenuation' (that constantly overheats -at high attenuation- causing hi-fi buff's to fear losing their prized kit. i.e. the up/down/runaway volume).

I understand completely the frustration, however, I've not given up on my beloved 840E (pre-amp); believing I can find a suitable (much higher quality/power/heat-dissipation resistor-relay 'board' (or necessary parts).

To think that CA couldn't fix that what plagued the 8-400 series (6-10 years on -in the 8-500 series is both laughable -and sad. For, as you say, CA otherwise has shown it can make some impressive kit.

Go figure,


allhifi's picture

Hey Frems: Solid review. Cambridge Audio has some fine product; the 851A reviewed case in point.

A few years back I also stumbled, fortuitously it proved, on a CA product; 840E preamplifier. One heck of a pre -a rare (musical) treat.

Then, as now it appears, CA has both some impressive engineering/listening 'chops', but also some glaring faux pas; the 840E's resistor/relay volume attenuation used under-spec'd (power/heat) resistors tat result in 'runaway/ shorting' volume level -replete with accompanying pops, crackles ... hellish fear -of our beloved hifi (amps/speakers).

I, as you, agree:

" ... My only caveats concern its .... nice little plastic tone controls, one of which got stuck and stopped working ...hermetically sealed, military-spec pots and switches? If they work in an F16, they'll surely outlast all these fashionable, programmable, namby-pamby, chip-based interfaces."

I'd add; dispense with those ridiculous "tone" controls altogether. And return to using a higher-spec'd resistor/relay volume implementation.

If only CA could rid themselves of a few of these glaring mis-steps, they'd have a stunning, high-performance, high-value offering that would satisfy audiophile's (rightful) expectations.

peter jasz