Review: Cambridge Audio Edge M: Mono power amplifier

Review: Cambridge Audio Edge M demonstrate outstanding dynamic capabilities, especially with large amplitudes and exceptionally well made.
4.5/5 - (4 votes)

Review: Cambridge Audio Edge M- A few years ago, when the Edge A DAC integrated amplifier, the first model of the new top line from Cambridge, came onto the market, I was somewhat surprised. In a positive sense, because I hadn’t expected such a minimalist-elegant design from the beautiful-living-with-hi-fi corner in view of the otherwise conventionally designed Otto normal devices from the British. Now the brand new Cambridge Audio Edge M mono power amplifiers (8,998 euros / pair ) are on the tester shelf – and they also look damn sharp.

Speaking of hot: I don’t want to talk about eroticism now, but … Cambridge has understood that the pride of ownership, which is so important for customer satisfaction, begins with unpacking, and has ensured a corresponding experience with the Edge series. I hardly know of any hi-fi device that on the one hand was literally thrown into the shell so safely and well-thought out and on the other hand staged the entire unveiling process so effectively. In the last step, you remove the leaves from the curved shapes of the monos from a black velvet dress, then find a soft, delicately white translucent silicone tape that lies in the recess of the Edge M surrounding the lid to protect the (or in front of) the cooling ribs. delicately textured, smooth surface … Well, yes.

Worked neatly

Be that as it may, the British are obviously impressed by clever detailed solutions and their accurate implementation. To name just one example: If you want to lift the said cover, you don’t need a cumbersome cordless screwdriver orgy. Instead, there are two deep-hole Torx screws on the back of the Cambridge Edge M. These screws are to be understood as securing, because they can only be screwed out exactly to the outer edge of the holes in the rear wall. Then they are no longer in the way of the bolt of the lid, which means that it can be pushed back and lifted off. Simple, ingenious and executed with absolute precision in the hundredth of a millimeter range. Incidentally, like the entire case including the interior. The finish of the matt gray front is flawless, the contrast to the black cooling fins is exciting,

Cambridge Audio Edge M: Metallfolie unter dem Deckel

All of this seems extremely solid and trustworthy. And Cambridge is not too bad to openly make it clear by means of a large print on the back wall that the development in the UK and the assembly takes place entirely in China. In view of what is offered, I really don’t know which quality adjustment screws a European production facility should still turn.

Double double whopper

Cambridge Audio Edge M von innen

As I said, this also applies to the innards of the Cambridge Edge M Monos, the center of which is shaped by two 325 VA toroidal transformers in a piggyback formation. That is not exactly oversized, but perfectly adequate. And, moreover, it is less about quantity than about quality: With this “double toroidal transformer arrangement”, the mirror-image stray fields of the transformers should (for the most part) cancel each other out. Another toroidal transformer with a significantly smaller 42 VA is mounted vertically behind the front panel and is responsible for supplying the input stage. There are four specially made capacitors for Cambridge on each side of the housingwith 10,000 μF each, so that each monoblock has a total sieving capacity of 80,000 μF. Eight power transistors in pairs are responsible for the power amplification and can each deliver 200 watts (per pair). Another pair of transistors takes care of the Class XA circuit alone (I’ll get to that later), says Cambridge.

Sum game

Cambridge Audio Edge M. Rückseite mit Anschlüssen

Not only does it look symmetrical, it is. And fully symmetrical with two complete amplifier strips from front to back. Of course, Cambridge Audio offers unbalanced cinch sockets on the back of the Edge M in addition to the corresponding XLR inputs for control on: A small switch on the back tells the amplifier what kind of input signal you intend to feed it with. The internal signal processing then takes place one way or another symmetrically. This means that in the case of asymmetrical control there is an additional balancing stage in the signal path – and this fact (small spoiler) obviously plays a role in the sound test. In addition to the inputs and the loudspeaker terminals, which accept banana plugs and fork shoes, there are also symmetrical and asymmetrical outputs for looping through the signal. Only if you want to let go of two or more monos on each speaker, keyword: bi- or even multi-amping.

First class

Cambridge Audio Edge M: Mono-Endverstärker-Paar

The massive heat sinks of the fanless Cambridge Edge M indicate that this can potentially generate a lot of waste heat. Class D as a reinforcement principle is therefore more likely to be eliminated. Instead, Cambridge relies on a technology called Class XA. This circuit should combine the sound merits of Class A with the energy efficiency of a Class AB circuit. In conventional AB amplifier designs, where two complementary components each amplify a half-wave of the signal, distortion occurs at the point where the signal transitions from one transistor to the other. According to Cambridge, this transition point is normally exactly where the useful signal is quietest and the distortion is also relatively most relevant to hearing, namely at the zero crossing of the signal. Cambridge now adds a slightly increased bias, which shifts the transition point into the positive half-wave range. In practice, the edge amps work like a single-ended Class A design at low levels. A set of transistors (the one from whose work area the crossover point is now further away) remains more or less inactive until the signal reaches a sufficiently loud level and activates the “sleeping” transistors.

Cambridge Audio Edge M: Leistungstransistoren


The Cambridge Edge M offers a user-friendliness that is not always found in the high-end sector – apart from the rather steep weight of almost 24 kilograms per M power bar. For example, all devices in the Edge line can be connected with a 3.5 millimeter link cable (included), which forwards the on and off signals from the first device in the series to its fellow players. In addition, the power amplifiers automatically switch to energy-saving standby after 20 minutes without a signal, and even if the preamplifier does not provide a trigger signal, they switch on again when they detect an input signal. The waiting time from switching on to the activation of the outputs of around four or five seconds is also completely okay.

Sound test and comparisons: Cambridge Edge M

I’ll fall right in with the door: The Cambridge Edge M should preferably be controlled symmetrically, i.e. via the XLR interfaces. The Edge M thank you with a tighter, more airy, better defined and finer resolved sound image with somewhat more precise localization. What the cinch and XLR controls have in common is a tonally neutral gait without emphasis or underexposure of any frequency range. But since the absence of flipsides never catches the ear as aggressively as outstanding peculiarities, the first thing that stands out is the extremely gripping, energetic performance of the Edge M. Gentlemen!

Cambridge Audio Edge M mit Audio-Note-Lautsprechern

It doesn’t really matter what kind of bass or mid-range impulse is fed to the Cambridge Edge M; the monos make it a real spectacle. Not in the sense of “too much of a good thing”, but with a very positive connotation. I catch myself looking forward to the next bass slap from Marcus Miller in “Detroit” and the snare drum from Porcupine Tree drummer Gavin Harrison in “The Sound of Muzak”. Or the (too) fat produced bass drum in St. Vitus’To physically long for “Children of Doom” from the album of the same name. The Cambridge Audio Edge M do this with the lightning-fast response of a small-volume inline six-cylinder naturally aspirated engine and at the same time deliver the full, powerful pulling power of a turbo diesel (I’m still working on my car comparison rate).

Cambridge Audio Edge NQ Vorverstärker/Netzwerkplayer

I don’t really know it much better – neither from the Norma Audio Monos PA 160 MR (14,000 euros) nor from the large tube stereo power amplifier Balanced Audio Technology VK76SE (14,200 euros). There is no arrogance or hectic rush: The Cambridge Edge M have a stoic calm, confidence-inspiring stability and sovereign overview – not to the extent of the “volume-controlled output stage with analog inputs” ASR Emitter I (from 6,800 euros), but the English monos seem theirs acoustic volleys felt like shooting out of the transistors even faster than the colossus from Herford.

Tackled: bass and deep bass

When controlled symmetrically in particular, the Cambridge Edge M realize the entire bass range extremely precisely and in a controlled manner, differentiating even the deepest bass impulses as in Yello’s “Pan Blue”  with exemplary accuracy. With long-lasting bass tones like in Massive Attacks “Teardrop” (Album: Mezzanine) the M do not allow any droning or wobbling and draw the structures or texture of what is happening in an easily understandable way. In principle, they also do this asymmetrically, just not quite as stringently and consistently. They also sound slightly stronger in the bass. Mind you, these are very relative statements at the highest level of comparison – if you didn’t know that even more is possible symmetrically, you wouldn’t miss anything in cinch mode at first.

Cambridge Audio Edge M Frontansicht

Either way, the Cambridge Edge M deliver a little more pressure all the way down to the deep bass basement than the Norma Monos or the BAT VK76SE. With the right speakers, deep bass orgies can become a physically noticeable experience, and even the astonishingly deep bass capable compact speakers Grandinote Mach 2Ractivate the popometer clearly. The cheaper stereo power amplifier Norma Audio PA 150 (5,300 euros) seems a bit more cautious, comes with a little less pressure in the deep bass and is softer in response – overall (like its big siblings) a little more elegant and flowing than the Cambridge. But okay, that’s one of Norma’s core talents anyway. Before you get the wrong impression: The Cambridge Edge M are no fights, even if their dynamic main focus is more on explosive speed and force and a little less on tracking down the smallest nuances of energy. But this, too, is quite simply a relative classification based on a very high level of comparison.

One thing is clear: the keynote

Cambridge Audio Edge M: Detail vom Innenleben

The taut, powerful bass range is followed by an earthy and supple basic tone . Jaco Pastorius’ electric bass purrs happily like a kitten and allows you to easily understand even fine structures. Thanks to their transparency alone, the Cambridge Edge M focus on this area a little more psychologically than the Norma Audio PA 150, which is less differentiating here excellent stereo Italian.

The clearly different interpretations of the timbre spectrum are a matter of taste and have a direct effect on the perception of the fundamental (and mid-tone) in particular: the Norma PA 150 transmits this aspect with a silky, matt, shimmering and fragrant, fine floating effect; The Cambridge Edge M handles the overtones with a haptically textured and drier, but by no means pale . For example, the cellos creak and grate in Agnes Obel’s “Familiar” with the British women clearly woodier, less smooth. And while I’m a fan of that silky Norma sound, I think this rougher rendition is a little closer to the truth, even if it may seem less romantic to some. But that’s mostly how it is …

Either one or the other?

Cambridge Audio Edge M: Ringkerntrafos

The mid-tone of the Cambridge Edge Monos is inconspicuous in the best sense of the word. They serve the articulation of singers in a differentiated and precisely timed manner, sibilants have just the right amount of sharpness when required, and the Edge M transports the overtones of voices and instruments at least as openly as my Norma Audio PA 150. It never becomes insubstantial here as there. The Cambridge Edge M would probably not attract the attention of an audience streaming past the listening room at hi-fi fairs, with its center design that is more music-friendly than effects-grabbing. But that is precisely what should be understood as a compliment.

An example: The acoustic guitar in “Car Song” by RM Hubbert, Aidan Moffat & Alex Kapranos– like the Obel cellos – is not quite as spectacularly glistening and therefore in my opinion more natural than with some other amps that change the real sound signature of the acoustic instrument. The fact that the Cambridge Audio Edge M chase the guitar’s transients out of the speaker drivers really fast and to the point deserves respect. Often – even in this price range – an amplifier emphasizes either one or the other – not the Cambridge Edge M.

Long, loud and stress-free

Cambridge Audio Edge M und Edge NQ im Rack

The symmetrical control of the mono amplifiers also has a positive effect on the treble. While a small but noticeable amount of air and resolution remains unused compared to the Norma power amplifier, the asymmetrically controlled, the Cambridge Edge M bring this to the ear without problem in symmetrical operation. The resolution of the frequency upper room is absolutely appropriate for the class, and its character is more objective and undisguised than with the silky, beautiful drawing Norma-Amp. And above all seamlessly integrated into the overall picture. Listening never gives the impression that there is a lack of information, and the British monos never draw the listener’s attention to aural nonsense when there is so good music to be heard.

The cleanliness, the black background, which the Cambridge Edge M (not only in the high tone) allow for all of this, conveys a very special calm. Does that sound unspectacular? Is it. And that’s a good thing, because unlike the laser light emitters under the amplifiers, you can hear for a long time, loudly and stress-free, without the ears sagging and the eyelids starting to twitch.

Cambridge Audio Edge M von oben

Space and figure

The image sharpness and the spatial differentiation also benefit from the symmetrical operation. It is interesting that the space spanned by the Cambridge Edge M has clearly clearer boundaries than the one designed by the Norma PA 150, for example. The size of the stage varies with the respective recording from tight and intimate to cinemascope-sized. The Norma PA 150 does this trick just as well, but it is not so convincing to define the (virtual) walls of the recording room: At first it may seem a bit more generous, at the second it is a bit more “frayed” at the outermost edges. All in all, what happens with the Edge M takes place fairly precisely on the loudspeaker level and goes into the depths of the room when the music material requires it. Not least because of the outstanding impulse speech, the M manage to sound involved and direct, without having to approach it spatially head-on. Different tastes or not: As in terms of tone colors and overtones, the Cambridge Edge M seem to me to stay objectively very close to the facts.

These honest workhorses with model genes and no-bullshit attitude are among the most universally applicable power amplifiers under 10,000 euros that have come into my rack so far: Tonally incorruptible, dynamically explosive, sparkling clean and transparent with brilliant power reserves even for high demands the sound level. Because you can connect several monos in series, there are hardly any limits to the play instinct in this regard. And because the Cambridge Edge M play so neutrally, I don’t really see any restrictions in choosing a (appropriate) partner. Musically, they also cope with all genres that one can imagine, but they particularly shine with dynamically demanding and complex music that suits the precise control and clear cleanliness of the Edge M very much.

Restrictions? Listeners who are explicitly looking for a silky, fragrant melodious sound in the dim chimney room of high fidelity, or who want to lose themselves in intellectual analysis instead of enjoying music, are encouraged to choose appropriate alternatives. The Cambridge Edge M don’t afford any extravagance and are something like the best buddies, with whom you can really party, who will still bring you home safely and reliably after the party, if need be …

The Cambridge Edge M …

  • are neutrally tuned mono power amplifiers across the entire frequency band.
  • have a tight yet very powerful bass that goes extremely deep and even there still acts with outstanding control.
  • connect to the bass a textured, grippy basic tone.
  • have an inconspicuous, homogeneous mid-tone with very good transparency and realistic substance.
  • produce a little more details, gloss and air in the upper frequencies in symmetrical operation than in asymmetrical operation.
  • In absolute terms, they are not the greatest analysts, but integrate the clear and objective high tones in a way that is useful for the purpose and the music.
  • demonstrate outstanding dynamic capabilities, especially with large amplitudes.
  • radiate a special, subliminal calm.
  • build the virtual stage pretty much around the loudspeaker level.
  • delimit the stage surprisingly clearly, the dimensions of the same are almost arbitrarily variable depending on the recording.
  • only know competition in their price class when it comes to the sharpness of the edges of the display of instruments and voices, especially in the center of the stage and with the absolute high-frequency resolution.
  • are exceptionally well made.


  • Model: Cambridge Audio Edge M
  • Category: Mono power amplifier (transistor)
  • Price: 8,998 euros / pair
  • Dimensions & weight per piece: 150 x 460 x 405 mm (HxWxD), 23.6 kg
  • Color: Lunar gray
  • Inputs: XLR or RCA
  • Outputs: speaker output, loop output (balanced and unbalanced)
  • Output power per monoblock (<1% THD + N): 200 watts at 8 ohms, 350 watts at 4 ohms
  • Power consumption: max. 1000 watts, standby: <0.5 watts
  • Guarantee: 5 years