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Cambridge Audio Azur 840E Preamplifier & 840W Monoblock Amplifiers Review

Doug Schroeder reveals how the Cambridge Azur 840E and 840W amplification system fared in today's landscape

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Cambridge Azur 840EW

Already having been intrigued, and subsequently surprised, by the Azur 840C player I felt it only natural to investigate the newer offerings of the Azur line, the 840E Preamp and the 840W Amp. They have a lot to live up to, as the player is a pleaser. If this combo would surmount the challenges and rise to the same level of performance, Cambridge would have a trinity of tasty components worthy of consideration by anyone who wants better than average separates or a quality one-brand system.

It seems every few years the hot manufacturers swap positions, with newer, cutting edge designs taking the lead. Jockeying occurs even in the middle of the High End pack, where Cambridge holds a solid position. While more recognizable in Europe, the name seems to be gaining ground in America as their gear becomes more upscale in its performance. The Cambridge line is to me a “European Parasound”, only a bit less ambitious price-wise. Both have smart designs with respected performance. The Cambridge design team caught the leading edge of a wave with the Azur 840C player, which you are welcome to read more about. Now they are in position to capitalize on it through their preamp and power amp. I will tell you if they succeeded.

Just how many features can be packed into a component? One might think that was the driving ambition of Matthew Bramble’s design team. Nearly every conceivable option, and a few that the majority of owners would not have conceived, has been incorporated. I could spend the length of a normal review simply discussing them but I won’t. I’ll let the hefty, thorough manuals flesh out the intricacies of the operations while I will point out the salient features to two-channel enthusiasts. Before I leave discussion of the literature, I appreciated the Quick Start guide enclosed with the 840 series components. It is a thoughtful way to help busy buyers get their rig set up. The 840W has another polite gift for purchasers, a low voltage trigger cable and a cable clasp for wrapping up untidy cables; these are signs that Cambridge is thinking about the real world needs of the buyer.

Contemporary and clean marks the style of the Azur line. Both the deep charcoal colored player and the brushed silver pre/amps in my possession are simple, but aesthetically pleasing in the way that a crisp dollar bill is simple but enjoyable. Tiny blue LED’s contrast the wide, strong looking facade. A light gray illuminated display on the preamp matches that of the player. Many functions of the remote carry over between the player and amp; when the amp is selected one can have nearly complete control over it using the CD player’s remote. Since I had the player’s remote handy I never bothered using the one for the amp. An “amp” button on the player’s remote toggles commands to and from the amp. Even the modular packaging is a thing of wonder; utilization of the same scheme is evident in all three pieces. Some boxes sustained hits en route, but no components were scathed.

The Azur series is a statement grouping, displaying Cambridge’s genius and lavishness in packaging features for the dollar. A partnership with Anagram Technologies for the 840C player led to a cascade of development, first with the 840A integrated, then the 840W amp and 840E preamp. Once the amp was finalized, a return visit to the integrated was justified, thus the generation 2 class XD technology was incorporated in the 840A v2.

Just as I was pleasantly surprised by the presence of a digital input on the 840C player, so also with this combo I was delighted by the panoply of functions. The preamp’s front has a headphone jack, “Direct” (bypassing tone controls) function for each input, and one touch access to all seven of those inputs, not counting full tape deck compatibility.

Looking in back, such a dizzying array of connections makes one wonder what isn’t incorporated into this piece? Here is what I found: Low voltage trigger linking the pre and amp, IR emitter input, Control Bus in and out, RS232C port for custom installations, and the proprietary “A-Bus/Incognito” multi-room outputs, allowing for additional PS5 Power Supplies for multi-room installations which would incorporate the use of A-BUS KP10 Keypads and Incognito AS10 Active Ceiling Speakers. Cambridge is seeking to bridge the gap between audiophile two-channel sensibilities and real world quality multi-room AV lifestyles.

I wasn’t motivated to wire my house to test the Incognito system; I’ll leave that for an AV magazine reviewer. My attention was the two-channel capabilities of the Azur team’s efforts. To that end the unit has switchable single-ended / balanced #1 and #2 inputs. The subwoofer out features a choice between flat (unfiltered) signal or application of a 200Hz Low Pass filter (the main outs remain full-range regardless of this setting). Balanced or single-ended preamp outs are supplied. The unit has a power rating of 230V and sports a detachable IEC.

Would you believe that the amp is just as feature-laden? When it has indicators on the front for STANDBY/ON, OUTPUT, PROTECTION, CLIPPING, BRIDGED, and MONO it’s going to have some extra doodads on the back. Those doodads are comprised of easily gripped terminals (spaced a wee bit close for larger spades; watch the positioning of spades and make sure they are locked down well.) and the expected full complement of both RCA (single-ended) and XLR (balanced) inputs as well as loop outputs. Those outputs are to be used in conjunction with the Control Bus system for custom installations using more than two amps. The RCA/XLR inputs are selected via a clearly marked toggle switch for each channel. Two other switches are conspicuous, one for “Stereo/Mono” and the other for “Mono Mode” versus “Biamped Mono”.

Cambridge Azur 840E front

Here’s how these last two switches work; the “Stereo/Mono” switch determines if the unit will operate overall with two channels or one. The “Mono Mode” switch determines how many Monos you get. Those Cambridge folks are so accommodating that they insist on offering you the option of not only one mono, but two! Here is the breakdown of what would happen based on the switch placement:

Top Switch Bottom Switch Result
Stereo Bi-Amp Normal stereo function
Mono Bi-Amp Two Mono Channels per 840W
Mono Bridged One Channel per 840W

In the event that the top switch were to be put on “Stereo” and the bottom switch on “Bridged”, the amplifier “would simply go into protection… no possible damage,” according to Daniel Jacques of Audio Plus Services, the U.S. Importer of Cambridge. Only the left input of each amp is used in “Mono Bridged” mode, and the directions seemed to indicate only balanced connections in this mode. When one considers bi-wiring, the complexity of just hooking up speaker cables is potentially daunting! But fear not, visuals for each option are meticulously laid out in the manual along with instructions.

This information is critical to obtaining the ultimate performance of the 840E/W combo. The power yielded by each amp in either stereo or “Mono Bi-Amp Mode” is 200wpc into 8 Ohms, 350wpc into 4 Ohms. However, when the entire amp is mono bridged it becomes 500wpc into 8 Ohms and a whopping 800wpc into 4 Ohms. For those seeking a capable stereo amp for general purposes one 840W will suffice. However, those looking for high quality solid-state amplification will want to move to the “Mono Bridged” mode, that is, obtain two of these units. The performance elevation is such that it is easily merited.

What else can this amp conceivably have? I mentioned the RCA/XLR outputs (I am speaking of the amp here), which are technically named LOOP OUTPUTS by Cambridge. If you want to play on the playground of the “Really Complex Rigs” use these outputs to connect a few more 840W amps! I think that’s leading back to the custom install thing, so I’m staying away from it. Then again, four “Mono Bridged” 840W’s would be cool…

But, if I did that, I’d have to get an additional air conditioner just for the listening room. Yes, they run hot, as hot as notoriously high-power Class A amps or behemoth tube amps. They aren’t nearly as hot as the surface of the sun, nor singe the finger upon contact (thanks to the perforated protective casing over the heat sinks), but they do kick off prodigious amounts of heat. My listening room is so acoustically well insulated that having only one HVAC supply and return I need shorts in the winter and sweats in the summer. The room absolutely blocks dissipation of the temperature through the walls. I get chased out after about 2 hours of nonstop listening using the Azur amps. If your place is more open with good circulation this issue will be less noticeable. It is unlikely little ones would be seriously injured by the amp’s heat, but it’s still best policy to keep them away.

10 Responses to Cambridge Audio Azur 840E Preamplifier & 840W Monoblock Amplifiers Review

  1. Rudy Velickovski says:

    Hello, and thank you for the wonderful review of the Cambridge Audio 840W Amplifier.

    I just went and bought one from a local dealer and I’ve fallen in love with it. Your review was bang on in all aspects of the units sound quality.

    I had a question in regards to the bridge mode of this unit. I would like to buy another one and use them in the mono mode to increase power output.

    Everything I’ve read when it comes to bridging stereo amps, is that is leads to reduced sound quality, primarily distortion, greater cross talk, etc.

    I do not want to impact the quality of the sound in any way, at any cost. Did you notice anything by putting this amp in bridge mode?

    Thank you kindly

  2. Rudy,
    God’s Joy to you,

    Perhaps the answer can be best answered in terms of measurements vs. the listening experience. The measurements may be less tidy with use of two amps in Bridged mode, however my experience has been that use of two amps is always superior to use of one in stereo mode.

    Now, if a person is suggesting that, say, a single 250wpc amp would be superior to two 125wpc amps run in a passive biamp mode, I will not argue that. Typically one would get better results from a more robust single stereo amp. But that does not preclude improvement by addition of a second stereo amp and running them both in Mono mode.

    I still use the two Pathos Classic One MkIII tube hybrid integrated amps in Mono mode because they are so blissfully rich and attractive sounding. So, in my experience the addition of a second amp always improves, perhaps not as much as a more expensive single stereo amp, but enough that it is well worth pursuing.

    The Azur was glorious when used with two units in Bridged mode; I preferred to run them that way in most installations, if that helps you to decide.

    Douglas Schroeder

  3. David says:

    Hi Douglas

    Thoroughly enjoyed your review of the 840E and 840W’s, so much so that off the back of it I went out, auditioned and eventually bought the combination. I have since sold the pre-amplifier but have kept faith in the 840W’s, so much so that I have managed to acquire another two, so now have four in total.

    My question or comment is in relation to their ability to drive speakers and impedance handling. Up till now I have been running all four in Bridged Mono mode running a pair of tri-wireable, three-way, 8 Ohm ATC scm35 apeakers (two per each speaker one for LF, and one bi-wired to M and HF terminals), and whilst the sound is superb, the treble isn’t as precise as I would like, thus I decide to add a supertweeter (8Ohm), and here is where my problems started.

    The supertweeter did exactly what I wanted it to do in terms of sound, however the amps started to run very hot, far hotter then they had in the past (you know how hot they can get), to the point that you could quiet easily burn yourself – something is not right? Do you think the supertweeter has altered the impedance figure and as such the amps (in Bridged Mode) are finding the load too difficult? and if so, should I switch them to Dual Mono mode to avoid problems?

    Also, the manual does not give the amps “wattage” into 2 Ohms, so does this mean that Cambridge don’t recommend the amps drive 2Ohm speakers, or that they simply can’t.

    Many thanks, I always enjoy your reviews.

  4. James Romeyn says:

    Mr. Schroeder,
    Hope you are well.

    I would most likely run one stereo 840W, not two. It would be nice to get a handle on the heat issue for one amp. Recently I employed one Atma-Sphere S30 OTL (current model). How might you compare the heat? Do you know how many watts the 840W dissipates while idling? For a thoroughly burned-in sample, what is estimated duration from “off” to close-to-maximum performance?

    The load is two separate full range speakers per channel (one is an “effects” system with late-arriving output). The impedance is ruler flat above the bass range, allowing the two speakers to wire either in series (ruler flat 20 Ohm above the bass range) or parallel (ruler flat 4.8 Ohm above the bass range).

    My lifetime experience with SS amps is the higher the impedance the less audible and less intrusive are noise and distortion spectra. I presume therefor the 20 Ohm load is preferred if 90W is enough power, which it might be (low 90 dB sensitivity). Your comments appreciated.


  5. Effi Ceon says:

    Thank you very much for this detailed review. It was a big help for my decisions. Running now 2x 840W biamped with Quadral Aurum Titan VII and it will be combined with 840E soon.
    Kind regards

  6. peter jasz says:

    The Cambridge Audio 840-E must be the most under-rated preamplifier in the history of Hi-Fi.

    It possesses the rare quality of excellent transparency/resolution with tonal realism; fleshed out instrument tone/hues from top-to-bottom. The entire frequency bandwidth is impressively revealed with particularly rare (but most welcome -and essential) low-frequency transparency and detail. The remainder of the music spectrum is equally finely resolved, nuanced and articulate, imbued with a graceful finesse – very rare, very desirable qualities.

    The interior layout precision is also impressive. As is the precision resistor/relay volume implementation.

    The 840-E also has ample inputs and control flexibility. The chassis styling, ergonomics and build quality is first rate.

    Highly recommended.

    peter jasz

  7. Marcin says:

    I’m reading about the Cambridge audio AZUR 840e & 840w set getting encourage to upgrade my current system which is Focal Chorus 836v with old NAD power amp C272 and Yamaha RX-A3040.
    1. I would appreciate your advice if, in your opinion, CA 840e+840w would be the good match with my Focals? Anybody tried that ?
    2. Would CA 840e+840w be an major step up in my stereo system ? as it cost a bit …

    Thank you for your advice

  8. peter jasz says:

    Reviews for the 840 E/W are collectively excellent -for good reason.

    Clearly, the reviewer heaps more praise upon the amplifier (W) than Pre (E).
    But, as a 840E owner (and long-standing experienced audiophile), rest
    assured that the 840E preamplifier is a superb line-stage. The resolution/clarity,
    layering, dimensionality, life-like musicality, low-noise and striking micro/
    macro dynamics are all very impressive. Interestingly, the Cambridge 840E
    wasn’t even on my radar as a possible/suitable contender. Thank goodness I
    stumbled upon it.
    ‘Pop’ the lid, and you’ll discover a beautifully laid-out interior; attention
    to detail that shames that of Constellation (garage-build) components
    (that are priced 10X that of the CA -lol)

    The down-side (and it’s something to seriously consider) is the problematic
    volume-control circuit/relay’s that fail early; resulting in nasty ‘run-away’
    ‘ volume’ levels, and or seriously loud “crackling” sounds that can easily take
    out tweeters. This appears to be due to under-spec’d relay’s, and very high
    internal heat levels; remarkably, there is no top plate ventilation on the 840E !
    (Removing the top-cover reveals ‘scorch’ marks on the underside – a sign of far too
    great heat build-up. How such an oversight escaped CA engineers is difficult to

    In any case, (superior quality) relay replacement is demanded, as would be addressing the
    ventilation concerns. So, if a used 840E becomes available, although a superb unit,
    be forewarned that a few-hundred dollars in repairs/upgrades WILL be required.
    The 851E is the 840’s “successor” -and possibly remains current. However, it’s NOT the same
    (not near as good) preamp.
    BUT, it does come with top-plate ventilation holes; the top-cover also ‘fits’ the 840E, albeit
    the color/finish does not match that of the 840E. Perhaps the 840W top plate for some much
    needed ventilation ?

    I have the amazing Classe CA-2100 as a main amplifier; the combination is amazing.


  9. Duane Gosa says:

    The 840E model is problematic.. due to the control knob for volume.. it went ballistic and blew up my 2000 dollars power amp. I turned it all on and the pre amp went to full volume before I could get the power shut down..I called Cambridge Audio and they knew about this issue, now I know mine is out of warranty which they were quick to point out. They said a few of these got out and is was not worth a recall.. so I bought the Vincent 232 power amp.. love it..but before I can turn anything on I have to make sure that the 840E is not going to do it again, once I get it stable then I turn on the rest of my amps. When I talked to them about this, they said I could ship it back for repair which they would charge me for. I live in the states they are in England and I would have to pay for the shipping and I should have the original box..or they told me that they would give me a half price on a newer model.. What a joke. Never again will BUY their product. They knew about it and still sent them out.. When I read the reviews on this pre amp oh it is so great, bullshit…no help, if they knew they had an issue like this these should’ve never been sold..some great reputation!!! Never again..this has been some time ago when I complained about this but it still pisses me off that they would not do the right thing.. who knows when I would’ve got it back and they were going to charge me for the repair also.. no good, never again.. such a great company, they do not stand by their product…yes again it was out of warranty but what pisses me off they knew about it..junk..I fight it everyday.

  10. duane gosa says:

    My 8403 preamp blew up m components. Do not recommended any Cambridge Audio stuff again, no support. Also I have a DAC from them, it quit in a month and I have called and left my number, no way will I buy this line of product..pisses me off. They do not stand behind their the product, it’s a shame that these bad ones got out but did not stop them for ending them out of protection.

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