CAMBRIDGE AUDIO CA840A v2: What an amp!

Submitted on: 15 Feb 23

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Cambridge Audio is a British company and one of the better-known island manufacturers of commercial audio equipment. Their portfolio includes a considerable number of devices, mostly in the lower and middle classes. It should be noted that the sale of “audio gadget salad” brings in a considerable amount of money because they are the most sold and collectively account for the largest share of the profit pie.

Cambridge Audio (hereinafter “CA”) was founded back in 1968 and had some interesting products that I didn’t have the opportunity to try. I won’t go into detail about the company’s history, but after a series of ownership changes resulting in inconsistent market approaches, in 1994 CA fell under the ownership of James Johnson-Flint and his business partner Julian Richer, who also owns a chain of audio/video equipment stores under the name Richer Sounds. Perhaps because they can be bought like in a department store, the majority of CA devices come in boxes with handles for carrying – practical but not “puristic” :).

I have ambivalent feelings about the company itself: design in Britain, production in China. This combination is fantastic for the manufacturer’s profit and often detrimental to customers who buy devices for the long term. There are several reasons, but the essence is that back in 1998, if memory serves me correctly, CA sent plans and a sample of one of its amplifiers to a Chinese subcontractor. CA didn’t believe the subcontractor would be able to “copy” the device right away and achieve the required quality. However, the Chinese manufacturer succeeded on the first try and sent back an amplifier that passed the test.

However, one thing is trial production, and another thing is negotiations, quality over the long term, and so on. In China, you cannot start your own manufacturing company; instead, that job is done by one of the Chinese companies, often state-owned.

Big Western manufacturers like Apple, therefore, reserve huge resources from top-notch manufacturers like Foxconn (also known for relatively poor working conditions, training, etc., where it set up nets so workers wouldn’t commit suicide by jumping from factory and campus buildings). In this interesting constellation, small manufacturers like CA (small compared to financially strong tech companies) grab what’s left. On the other hand, Chinese companies often hire subcontractors from northern China, which is less developed than the south, cheaper, and, of course, of poorer quality. In the end, all the trouble spills over to the customer.

Quality control of the final product is essential: the aforementioned Apple is able to establish its quality standard, while it is very difficult for small companies to do so. Of course, things are improving, but slowly. However, it’s not all about the current quality of the final product: it also concerns the long-term quality of components such as passive ones (capacitors, resistors) as well as mechanical electro elements – switches, buttons, encoders, relays, etc. You can’t imagine how much new devices suffer in the long run because of such things.

I remember when I was supposed to write a test about the CA740A amplifier – something was rolling inside it, it seems like a plastic part, but I wasn’t sure. And the amplifier was new. Also, on the internet, there are a lot of testimonies about encoder failures on the CA840A v1.

Don’t think CA is the only manufacturer that operates like this: NAD is no better either, the capacitors I found in the PP2 phono amplifier and NAD C162 preamp would be embarrassing to put even in a children’s toy with a lifespan of one year. Harman Kardon isn’t much better either – on classifieds, the respected HK990 monster uses desperate electrolytes. The logic is “take the money, let it last a couple of years after the warranty”… But enough barking…

This, of course, undermines not only the customer but also the great effort of engineers to make a quality device, which ultimately suffers from compromises imposed by some quality management manager on behalf of the business, who, in turn, greedily wants profit and constant, often nonlinear – so-called inorganic growth.

CA made a significant leap in digital devices (CD players, DACs) around 2005 when it started using solutions from the British company Anagram Technologies, but I won’t go into details because the topic of this text is the CA840A v2.

The amplifier hit the market around 2008 as a modified successor to the CA840A model. I don’t have precise information about what was actually modified, and it seems to me that perhaps some slight tuning and replacement of components with higher quality and less prone to failure were done, but I can’t prove any of that, nor did I have the basic version of the CA840A on a comparison test.

Let’s start from the beginning: 2×120 W at eight ohms, with a mediocre damping factor of 110 and a weight of 15 kilograms indicate that it is a serious upper-class amplifier. Its price was 1,500 EUR, which is not a small amount.

While working for the magazine, I encountered Chinese products numerous times, including those made in China but designed elsewhere, and each of them had a flaw that couldn’t be overlooked: whether it was poorly screwed, exposed screws, poorly executed interior painting, low-quality components, misaligned connectors, or nuts protruding over the print on the rear panel as if they were designed by amateurs… or sloppy workmanship where it’s less visible or something else entirely, but that’s how it was. Today, even domestic Chinese manufacturers have gone much further, often producing excellent devices with an outstanding quality-to-price ratio that is sometimes unmatched by Western standards (I say this with caution, of course).

Why do I say this? Well, because the CA840A v2 is truly a mechanically precise amplifier, with really good quality in a not-so-affordable price class. The rear connectors are plentiful, and I particularly liked the eight inputs, the first of which can be balanced or line-level. However, personally, I’ve never liked amplifiers that have balanced inputs and immediately convert them to single-ended using a regular operational amplifier, so I won’t test that this time because the 840A v2 works just like that.

I also like that the input names can be read no matter how you look at them: from the back or from the top, because they are written in a mirrored manner in two ways, symmetrically. The quality of the connectors is decent, nothing to faint over, just commercial. The speaker terminals are also not bad.

The top cover is unexpectedly robust and has two rows of openings for each of the monoblock output sections. On the sides are two wavy aluminum covers, everything is very nicely integrated. This amplifier heats up quite a bit, just so you know, so it really needs cooling. It’s not Class A, but the XD system used by CA requires more airflow to operate.

Manufacturers often mention how thick the front panel of the device is – as if we’re talking about the bumpers of old Volvo cars. Another example of today’s idiocy of both manufacturers and buyers – as if it matters how thick it is and how much. Completely unnecessary, just nice to look at for the fools.

The front panel is very well designed, and for the ergonomics of that time, it’s a solid five. The amplifier recognizes connected headphones and notifies about it, then turns off the speaker outputs. There’s also a direct mode without tone controls, which I generally find inadequate for bass, but at least they are relay-controlled, so you don’t depend on a 50-cent switch that will gather dust and tarnish, and then ruin the feeling of good sound.

The CA840A amplifier is, in fact, a huge symphony of relays: from the inputs, we come to the tone controls and relays that switch them on or off, and then to the volume controls with discrete resistors controlled by, you guessed it, relays. If you’ve additionally activated the “Volume Ramp” option, the device will change the volume from zero to the memorized level upon startup. It goes in reverse when turning off. However, each step of volume change is one relay click, so the amplifier jerks as if it has a bunch of Minions inside pressing buttons and somehow hardware programming it. I really liked it, although it’s more of an interesting gimmick (I’m talking about “Volume Ramp”) than a necessity. Otherwise, a potentiometer of this type must have cost the company quite a bit in terms of parts. I assume that their monthly relay shipment just for the 840A took up a significant part of the warehouse…

Of course, there are speaker output relays at the end.

The display is one of the nicest I’ve seen in 2005, with LED backlighting. The new model, the successor to the 840A, has the same display with inverted polarization film, so the letters are light on a black background instead of the other way around, it’s a bit of a joke, obviously, they’ve come as far as they wanted and stopped there.

Input names can be changed, volume display in units or decibels, display backlighting is roughly variable, and there are some amplifier protection parameters that CA emphasizes as if you were going to try to burn it all the time. If it’s as effective as they say, I can’t imagine a way to damage it during use.


Two toroidal transformers, one for the preamp, the other for the output section. The mass distribution is excellent, with a central part that has two large cast aluminum heat sinks. They also serve as protection around the large transformer, it’s wonderful how they’ve come up with it. On the left and right sides are two monoblocks, and there are also two custom-made filter capacitors (I don’t know who makes them for CA) with a capacity of 15,000 mfd each, totaling 60,000 mfd of output section filtration, very nice. The output transistors are Sanken, four per channel, complementary 2SA1295 and 2SC3264.

In the picture, you can see a plethora of Omron relays inside, and there is also a multi-room communication section that I believe very few people actually used, I would have preferred the money to go to something more useful, but oh well…


The sound:

Since I wanted this amplifier to be part of my working setup, it was important to me how it performs with headphones. Imagine someone using a 2×120 amplifier for headphone listening needs. However, a plan I abandoned included the eventual use of Bose Acoustimass 5 II speakers, for which the CA840A v2 is a total overkill in terms of sound quality – the Bose aren’t bad, but the 840A is good.

Maybe I haven’t said it before, but here it is now: CA knows how to save where most users can’t look. A quick look at the amplifier circuit diagram showed that they practically used the entire amplifier for the headphone output, along with the output section, but to avoid burning the headphones, they inserted one resistor per channel. This trick is as old as amplifiers themselves and has been regularly applied both fifty and thirty years ago. In recent times, integrated amplifiers have received their separate headphone amplifiers – for example, the Sony TA-A1ES has a serious headphone amplifier with an impedance selector that tells the microprocessor how to control the bias of said section via optocouplers. Unfortunately, CA has nothing similar, not even in the announcement. But that doesn’t mean it sounds bad in the end.

On my desk was already the Metz 10HE11, my favorite all-in-one system consisting of an amplifier, tuner, and CD player packed into a deep panel about 7-8 cm high. As a source, I used a PC and an excellent super-affordable Loxjie D10 DAC, as well as a serious Sony HAP-Z1ES audio server (with its own integrated DAC). Let me mention that the Metz is actually the T+A model K1 and that at the beginning of this century it cost around 1,650 EUR, so it’s a pretty serious device, but with only 2×38 W of power at 8 ohms.

I’ll say right away that CA excelled in the width of the soundstage that could be felt even through headphones, as well as in the musicality that I liked.

Yes, the headphones were Senn 580 Precision as well as AKG K601 and K550. The speakers were Elac FS210 Anniversary, quite analytical and demanding boxes that reveal the flaws of a bunch of devices.

The high tones were quite detailed but somehow lacked that dose of relaxation and transparency that I’m normally used to and that the Loxjie and Sony can reproduce without any problems. The dynamics were good, but at times I expected better, although I still can’t put this as a complaint.

What fascinates about the CA840A v2 is the pure reproduction on the path to neutrality. This amplifier is not easy to match, obviously, because it’s ruthless towards both others’ and its own mistakes – it hides nothing, and that can be a problem.

Through headphones

The sound, through headphones, had a certain stiffness in the sense that the bass retreated a bit and in some tracks (e.g., Paul Wellr – Shaut To The Top!) it’s clearly felt but it’s as if the amplifier is not allowing it to fully come through. The Metz (T+A) has no such problems; in fact, it might be overly soft on the bass, unlike the CA, which tightens everything in its grip, and sometimes I feel like it’s holding onto it too tightly.

All of this results in a reproduction that has many advantages but also drawbacks. The way the Metz (T+A) delivers emotions, with the downside of sometimes having a rounded bass, is unattainable for the CA. One of the things I planned was to replace the ordinary factory power cable with a higher quality one, and here’s the continuation of the text. The CA 840A v2 is full of operational amplifiers, with classic NE5532s, and from my modest experience, replacing them with some BB operational amplifiers, like the 2604, always improves the overall score, especially in the high tones. It seems to me that the 840 has much greater potential than it appears, just because of cost-cutting.

I shouldn’t forget: in a later stage, I compared the CA 840A v2 with the Astin Trew AT2000 Plus amplifier, but you can read about that in the Astin Trew review.

With a different power cable

From my collection, I chose the Transparent Music Link Plus power cable. The amplifier immediately gained positive sound layering, calmed down the nervousness, and the high tones gained another layer they didn’t have before, although the change in them was unsatisfactory. The bass gained volume, not as much as I would like, but significantly better. The difference with the Metz (T+A) is now smaller and perhaps a matter of taste, but I still preferred the T+A. Compared to my standard amplifier – a very good one (in its price class of 2,000 EUR in 2013), the CA was losing in every aspect. The sound was good for me, but Brian Adams (the song Summer of ’69) sounded more like a hoarse teenager who got a unique opportunity to sing at a graduation party but started to mutate and lost his voice. None of his strength.

I won’t mention the importance of interconnect cables nor elaborate on what I used, unfortunately, I don’t have more time to write about it in this case.

Through speakers

At a quiet listening volume of a few watts of power (position 40 on the volume scale) and an external ambient temperature of 27 degrees Celsius, the transformer temperature reached 48 degrees and each of the output transistor heatsinks reached 50 degrees – which is not much compared to Class A transistor amplifiers or the Harman HK990, which reached about 67 degrees using internal fans. Anyway, I recommend leaving enough space above the CA840A v2 so it can “breathe.”

I must admit that there are few amplifiers that have pleasantly surprised me like the “Eight Hundred Forty”. Knowing the models 740A and 340A, I didn’t expect much. I heard that the withdrawn bass was one of the flaws of this device, but I personally wanted to hear how it would behave with my Elac speakers.

I put through 840A v2 almost all genres of music, except for hard-core heavy metal and turbo folk. Cambridge performed excellently, with an emphasis on reproducing editions that lean towards the audiophile spectrum, where there are more details, space, and dynamics than, for example, in classic pop hits. This is quite normal and shows that the limits of its reach are not so low.

Right from the start, I’ll say what is usually said in reviews towards the end: CA840A v2 reminds me of the definition of a perfect amplifier – wire with amplification. Not every wire is the same and often colors the sound, but it probably falls into the category of electronic components that don’t color the sound as much as, for example, coupling capacitors or potentiometers. But let’s get back to the Cambridge: this amplifier has an extremely neutral character. Some would say its sonic characteristic is bright – which is only partially true if we define clean sound as bright. For me, it’s neutral and, more importantly, not tiring. I listened to it for hours and never felt any fatigue, unlike, for example, amplifiers in a similar category like Yamaha’s (A-S2000).

So, as leading characteristics, I mention its pronounced neutrality and phenomenally clean sound, without tiring the listener, as well as the bass, which I’ll discuss later.

The next characteristic is that the CA840 v2 is quite detailed for its price class: the soundstage is within the expected range, but the details themselves are excellent, especially in the mid-range, and very good on the highs – although sometimes they lack a bit of texture at the very top. The human voice is so pleasant, without problems with sibilance, gentle when it needs to be, rough when it is. In a word, without using various audiophile expressions, everything is in its place, commendable.

I noticed that the decay of tones is excellent, with all the small transitions that vibrate when a string instrument is plucked.

What impressed me is… the bass! It’s not right in your face, not pounding on the ears. However, it’s there just when it needs power. But what’s surprising is another thing: phenomenal dynamics and control of the lowest tones. Within some tracks (e.g., Private Investigations by Dire Straits), the bass at certain moments hits so hard – I know the track and exactly what to expect, but the CA840A v2 had such good dynamics and control, yet freedom in the bass that it surprised me every time – I would raise my eyebrows because I didn’t expect this from an amplifier that cost 1,500 EUR. The drum hit would simply “knock out” the listener at certain moments and disappear just as quickly. Incredible. From a technical standpoint, this speaks to a well-executed output section and power supply.

I also liked the consistency of the sound image, which didn’t have any noticeable flaws even at very loud listening volumes; there were no signs of image degradation. It seems to me that the 840 uses its 120 W very wisely.

When you read what I’ve written, you might think that I consider this Cambridge to be a perfect device. In its price class, it’s hard to find a competitor. Comparing it with Harman – the old 665 and the newer HK990, I can say that the 840 beats them, which surprised me especially in the case of the HK990. It’s also slightly better than the Arcam FMJ A32.

I also compared it with the Pioneer A-70-K, a completely different concept of a device, cheaper (1,000 EUR compared to 1,500 for the CA), and although the Pioneer has decent sound and is beautifully made, the 840A v2 was drastically better in every segment in which I listened to it. That much.

To get back to the 840A v2: don’t think that just because it’s neutral, the CA840A v2 is an easy player: this is a pretty tricky device to match, not because it’s picky but because it will show the difference in sound from the source and the speakers. I would especially emphasize the quality of the source: I used a lot of things with it – from a super cheap streamer and a cheap excellent DAC to a former top-notch player and streamer. The amplifier clearly outlined every, even the smallest, difference in sound. So, if, for example, the bass of the 840A v2 doesn’t suit you, check first if the problem is with the source or speakers, and that the previous devices didn’t perhaps overly amplify the bass. The same goes for mid and high tones, but I mentioned the bass because differences often occur in this part of the sound spectrum.

And what can I say in the end: I divide amplifiers into those I could live with and those I couldn’t. Cambridge Audio CA840A v2 definitely falls into the former group. Great for the money it cost and still a very good buy today.


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