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Cambridge CXA81 MKII Amplifier Review

Rate this amplifier:

  • 1. Poor (headless panther)

    Votes: 55 23.9%
  • 2. Not terrible (postman panther)

    Votes: 130 56.5%
  • 3. Fine (happy panther)

    Votes: 42 18.3%
  • 4. Great (golfing panther)

    Votes: 3 1.3%

  • Total voters
    230
That's true here too. I am not sure how the DAC performance was allegedly measured, since there is no DAC output. You cannot actually measure the performance of the internal DAC absent a pair of outputs coming straight off the DAC.
You are welcome to put the blame in the pre-amplifier/buffer stage. It won't absolve the company any more than me saying it is the DAC output. If a company can't make a buffered output stage that goes beyond 1.6 volt without saturating, they clearly don't care about fidelity. Also, keep in mind that vast majority of stand-alone DACs also have buffer stages post output of the DAC IC itself.
 
Behaving as ASR and its denizens tend to behave is not a way to be taken seriously by manufacturers. It's a way to be sure they ignore you, which by and large, they do.
You are wrong. The CEO of the company reached out to me on my review of the first revision of this product. This is why I am surprised they didn't take any of the feedback to heart and include it in the revision of the product. I have given high marks to them for their Phono stages. But sure, if they want to ignore me, that is perfectly cool. I provide the data to their customers who want to know.
 
If a company can't make a buffered output stage that goes beyond 1.6 volt without saturating, they clearly don't care about fidelity.

With respect Amir, that's going way too far.

This is an integrated amplifier- remember that. With an integrated amplifier, especially one without pre and main access, sensitivities for inputs and outputs can be anything they want as they are internal. The CXA-81 pre-out is just a bonus. I don't hear all the jumping up and down for the same anaemic levels coming from myriad AVRs as they have been for 30 years.

Much as we would like every preamp output to be a fully buffered, high voltage, ultra low THD+N, it can't be. Anyone wanting a high performance preamplifier to drive an insensitive power amplifier is not going to be buying a Cambridge integrated are they?

And sure, I'd like a tape out, but I'm old skool. :)
 
They revised the unit and didn't fix anything. I can't imagine what they think they revised!
They actually have a blog post with their engineering manager on this very revision: https://www.cambridgeaudio.com/usa/en/blogs/raising-the-standard

You can see what they care about:

Can you summarise the original vision behind the CXA81 and how it paved the way for Mk II? What aspects of the original CXA81's legacy did you want to preserve or enhance?

"CXA81 has evolved, developed, and improved as a product for many years through various models, even as far back as 650A to 651A, with an extensive redesign for CXA80. CXA81 has become a multi-award winning product, winning the What Hi-Fi? Best Buy award for four consecutive years.

At every stage in the CXA81 Mk II design process, we were aware that the CXA81 sound had been extremely well received, so we didn't want to move too far away from this signature sound, which we believe to be fun, dynamic, engaging, and exciting. Our main goal was to add an extra level of definition to the current signature sound rather than a major deviation."

Can you walk us through the most significant technical upgrades in CXA81 Mk II? How do these upgrades translate into improved sound quality for the listener?

The most obvious specification improvement was to upgrade the ESS Digital to Analogue Converter (DAC) from the ESS Sabre ES9016K2M to the ES9018K2M. Upgrading the DAC gave us noticeable improvements in performance, but we were confident there was more to come.

The main work on CXA81 Mk II was component tuning, divided into three sections: understand, improve, and refine.

Firstly, we had to understand the exact areas of the PCB layout that affect sound quality and determine the influence of each component. This was a painstaking task, following the full signal path and swapping in and out components to fully appreciate their effect on overall performance. For every step, we listened to the changes made and documented their impact. Only with this understanding could we move to the improvement stage.

Initially, the next stage focused on areas with the most significant effect on performance, switching between combinations of components from multiple suppliers. It is not enough to optimise one component at a time, as the interactions within different permutations can sometimes produce unexpected results (not all positive). It was an iterative process, taking months of meticulous work across many listening sessions. This phase of work resulted in five unique variants of tuned prototypes.

The third and final phase was to listen in depth to the five differing builds of units, using the CXA81 as the reference in each case. Three units were soon discarded, leaving two units, which our listening panel agreed, delivered on our mission – to build on the strengths of the CXA81 while providing another level of detail and a more expansive soundstage. There was a further round of mixing and matching to take the best elements of these two prototypes, resulting in the CXA81 Mk II tuning you hear today.

I think we have our answer on what went wrong here. Non-scientific/uncontrolled listening tests leading them to random changes of the components instead of close loop measurements. Let me show you the importance of that. Here is the spec for the ESS ES9016K2M (a $7 DAC):

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That would mean SINAD of 110 dB. We didn't get that even at optimal 1.6 volt out. DNR is well short of that as well:

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12 dB short there. On voltage, the chip spec shows 3 volts peak to peak which would be 2 volts RMS:

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So no, we should not give a pass here. You paid for a DAC that can produce 110 dB SINAD and 122 dB Dynamic Range but did not get that performance.

I am confident if there was any emphasis in the company to do well here, they could have achieved or come close to chip specs. Instead, they are proud of fluff reviews that could have been 5 star no matter what they did.
 
This is an integrated amplifier- remember that. With an integrated amplifier, especially one without pre and main access, sensitivities for inputs and outputs can be anything they want as they are internal. The CXA-81 pre-out is just a bonus. I don't hear all the jumping up and down for the same anaemic levels coming from myriad AVRs as they have been for 30 years.
You absolutely have heard it from me resulting in Denon and Marantz now producing healthy outputs instead of clipping:

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And no, it is not a bonus. It is a feature to use with more powerful amplifier which likely needs more drive voltage than the internal amp.

It is not even clear what the source of distortion is. It could very well be the same issue we saw with AVRs where their amp clipping caused the DAC to degrade. There was no reason for that.

I am sure you also remember those jumpers in the older gear that allowed you to stop the drive to power amp. Not here. You hook up an external amp yet the internal amp is still being driven. Marantz and Denon fixed this by having a "pre-amp" mode that disabled the drive to power amps. We don't have that feature here.
 
Well, think about that. Why don't they care and why didn't they just pull the outputs? Because ASR is irrelevant
Unfortunately, that’s not limited to ASR. In fact, the entire Hifi “industry” is irrelevant. ESS Technology’s rise as a top DAC chip maker wasn’t driven by audiophiles but by some Chinese phone companies which nobody cares at the time.

It’s always interesting to see people dream of raising a hifi company trying to achieve the luxurious prestige of Rolex and fail.
 
Unfortunately, that’s not limited to ASR. In fact, the entire Hifi “industry” is irrelevant. ESS Technology’s rise as a top DAC chip maker wasn’t driven by audiophiles but by some Chinese phone companies which nobody cares at the time.

It’s always interesting to see people dream of raising a hifi company trying to achieve the luxurious prestige of Rolex and fail.
ASR is not irrelevant though. It clearly affects the decisions of many manufacturers.
 
You are welcome to put the blame in the pre-amplifier/buffer stage. It won't absolve the company any more than me saying it is the DAC output. If a company can't make a buffered output stage that goes beyond 1.6 volt without saturating, they clearly don't care about fidelity.

Technically it's not saturation, since the preamp is still putting out voltage and actually gets cleaner as voltage goes up, but that's not the real point. It's likely distortion from the amplifier making its way back in--a problem Denon has still solved only by forcing you to disconnect the amps internally. But who buys this for preouts? They buy it for the included amp, which is objectively appears to be one of the quietest and very best of its kind for the price. And Cambridge appear to have made that even better in this iteration, surprisingly. (That said, a Yamaha is still just as quiet, includes phono, and is slightly cheaper. But maybe this has some other features that give it a leg up. I haven't looked at the featuresets all that closely.)

You are wrong. The CEO of the company reached out to me on my review of the first revision of this product. This is why I am surprised they didn't take any of the feedback to heart and include it in the revision of the product. I have given high marks to them for their Phono stages. But sure, if they want to ignore me, that is perfectly cool. I provide the data to their customers who want to know.

Perhaps. But most people know this as the SINAD site, whether that was intentional or not. And I have to think it plays a role in manufacturers ignoring what was a fair observation. I think they (along with the marketing department of any other manufacturer that bothers to look) know the emphasis on SINAD here is a race they will lose, so a review is not going to help them sell product. So why offer products for review, and why make changes that might satiate ASR when they can't "fix" their glaring SINAD "issue"? But it wouldn't take much of a refocus to change that equation. As my wife likes to say, it's a matter of tone. Here's a revised conclusion based on the same set of data, with a slightly different tone and take:

"Cambridge have usefully removed 5dB of noise over the prior iteration. This is now one of the cleanest linear power supply integrated amplifiers I have ever tested. The linear power supply will likely offer long-term reliability, and offers some useful headroom which many switching supply products do not. For those who are seeking this product mix, this is a likely to be a satisfactory and recommended combination. It is unfortunate that a phono stage is not integrated, however Cambridge does offer a very good separate phono stage which I have also reviewed favorably. That said, the pre-amp outputs, while remaining quiet and with a relatively high SNR, will have some mild distortion added over 1.6V output due to likely clipping of the internal amplifier allowing distortion back into the pre-amp stage, so gain matching may be important if you plan to use this with an external amplifier. If you need a full 2V and that mild amount of distortion on the last 3dB is unacceptable to you, or you desire something with a much higher SINAD, separates may be a better option."

That is still completely true, objective, and fair. It is not misleading in the slightest. Yet, it gets the point across without insulting the manufacturer and flaming them for a minor issue, and saying their product is "not recommended" and they they appear to have "done nothing" despite now being among the better ones in the class for those looking for something like this. With that approach, I think Cambridge and other manufacturers would both be more inclined to care about your feedback, and possibly even offer a review sample. That's good for everyone. This review is just proof they may as well not care at all. They take noise out, and get nothing for it because of an edge case on preouts. It just seems counterproductive to me.

Please don't take this as criticism. I intend it to be constructive because I do care that manufacturers make improvements to products based on solid engineering and science. Cambridge did some of that here. They pulled noise out of a product with a linear supply, which is not easy to do. Yet, they get no credit for that. Giving manufacturers credit where credit is due and not unduly chastising them for edge cases is, in my view, key to building credibility and influence with them, which I think helps the cause.
 
Ok, fine. But then why include the pre-outs at all if they are irrelevant?
To a recorder? A couple of subs? Separate headphone Amp? It would never occur to me to buy this to put a power Amp behind it. And as long as the match to the integrated Amp is good, the voltage seems fine (to me).
And again, why even buy this when you can get similar or better performance for much less money?
Now that's a good point. I don't think I'd buy it, but the DAC voltage wouldn't factor into the decision.

If you're going to push the "but it's inaudible" angle, that necessarily asks why should anyone buy this rather expensive (for its class) product?
Once we get into that territory it's hard to defend a lot of our gear choices, since changes often seem inaudible quite often and yet we enjoy it.
 
Ok, fine. But then why include the pre-outs at all if they are irrelevant?
To a recorded? A couple of subs? Separate headphone Amp? It would never occur to me to buy this to put a power Amp behind it. And as long as the match to the integrated Amp is good, the voltage seems fine.
And again, why even buy this when you can get similar or better performance for much less money?
Now that's a good point. I don't think I'd buy it, but the DAC voltage wouldn't factor into the decision.

If you're going to push the "but it's inaudible" angle, that necessarily asks why should anyone buy this rather expensive (for its class) product?
Once we get into that territory it's hard to defend a lot of our gear choices, since changes often seem inaudible quite often and yet we enjoy it.
 
And no, it is not a bonus. It is a feature to use with more powerful amplifier which likely needs more drive voltage than the internal amp.

It is not even clear what the source of distortion is. It could very well be the same issue we saw with AVRs where their amp clipping caused the DAC to degrade. There was no reason for that.

I am sure you also remember those jumpers in the older gear that allowed you to stop the drive to power amp. Not here. You hook up an external amp yet the internal amp is still being driven. Marantz and Denon fixed this by having a "pre-amp" mode that disabled the drive to power amps. We don't have that feature here.

You are calling out 1.6V (which is not the maximum anyway), when that is more than capable of driving the majority of power amplifiers being sold right now and has been for the last 50 years. Not edge-case DIY class Ds in a box or SINAD chasing low-gain toys from one trick pony companies. I'm talking multinationals who have been producing HiFi for 50+ years or more.

Yamaha's current TOTL ($AUD$14,000) power amplifier (M-5000).

Sensitivity for full rated power? 1V.
1725917532256.jpeg


Rotel's current model RB-1582:
1725917630548.jpeg


Rotel's current model RB-1552:
1725917687802.jpeg


Just one Yamaha professional range:
1725917781744.jpeg


It goes on and on. For every 10 amplifiers I can show you with a NORMAL sensitivity of 1.0 to 2.0 V on unbalanced SE for full rated power, you could dig up an edge example that might need 3V.

Edit:
Accuphase's current 2024 power amplifier range:
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1725920166867.png


1725920208613.png


1725920255887.png
 
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Once we get into that territory it's hard to defend a lot of our gear choices, since changes often seem inaudible quite often and yet we enjoy it.
That's fair to an extent. But I think a lot of this community, at least, is generally celebrating transparent electronics getting cheaper and cheaper, and even the SINAD chasing is happening at price points well below this particular product. And if one is chasing audible improvements to their system, this is not the place to spend your $1200. That price and it doesn't even include some sort of room correction or a parametric EQ in this day and age. (At least not that I could find, and trying to bring up the manual on their website just results in an error screen.)
 
My fifty year old IC based preamp (Crown IC-150) claims up to 10V output single ended.
Still have the companion DC-300 power amp?
Much as we would like every preamp output to be a fully buffered, high voltage, ultra low THD+N, it can't be. Anyone wanting a high performance preamplifier to drive an insensitive power amplifier is not going to be buying a Cambridge integrated are they?
Oh, I dunno. Are NE5532s going for more than a buck these days?
 
Well, let's look at Cambridge's own power amplifier: https://www.cambridgeaudio.com/usa/en/product/hi-fi/edge/edge-m

INPUT SENSITIVITY1.7V RMS (RCA) / 3.4V RMS (XLR)

It needs 1.7 volt which is already in distortion rising part of the DAC output!

This is silly stuff Amir and you know it.

At 1.7V output, the THD+N is at -95dB (according to your own tests) and you'd be driving the Cambridge power amp you linked, at 200wpc flat out!, with its rated THD of 0.002% at full power already dominating the 0.00178% THD of the preamplifier at that level.

Are we done yet?
 
This is silly stuff Amir and you know it.

At 1.7V output, the THD+N is at -95dB (according to your own tests) and you'd be driving the Cambridge power amp you linked, at 200wpc flat out!, with its rated THD of 0.002% at full power already dominating the 0.00178% THD of the preamplifier at that level.
That's an 8 dB increase in distortion. For zero, absolutely zero reason or benefit to anyone. 0.002% THD translates into SINAD of 93 dB. For the previous stage to not impact it by more than 0.5 dB, it would need to be 10 dB better or 103 dB.

Are we done yet?
Not with that kind of self defeating argument.
 
12 dB short there. On voltage, the chip spec shows 3 volts peak to peak which would be 2 volts RMS

Do you mean 3V peak-to-peak or 3V peak? The RMS value (sine wave) is different. For the first one 3Vpp equals to 1V RMS. Second value 3Vp equals to 2V RMS.
 
Do you mean 3V peak-to-peak or 3V peak? The RMS value (sine wave) is different. For the first one 3Vpp equals to 1V RMS. Second value 3Vp equals to 2V RMS.
If one read the ES9016 datasheet entirely, it is obvious that the 3 Vp-p (which translates to 1,06 V RMS) apply to each phase (+ and -) of a pair of differential output. That means a differential output voltage (between each phase) of 2,12 V RMS. It cannot be otherwise since the output voltage of each phase is defined by about 0.92x the analogue power supply AVCC, which is recommended to be 3.3 V DC in the condition of measuring the performances stated in the datasheet.
 
Technically it's not saturation, since the preamp is still putting out voltage and actually gets cleaner as voltage goes up, but that's not the real point. It's likely distortion from the amplifier making its way back in--a problem Denon has still solved only by forcing you to disconnect the amps internally. But who buys this for preouts? They buy it for the included amp, which is objectively appears to be one of the quietest and very best of its kind for the price. And Cambridge appear to have made that even better in this iteration, surprisingly. (That said, a Yamaha is still just as quiet, includes phono, and is slightly cheaper. But maybe this has some other features that give it a leg up. I haven't looked at the featuresets all that closely.)



Perhaps. But most people know this as the SINAD site, whether that was intentional or not. And I have to think it plays a role in manufacturers ignoring what was a fair observation. I think they (along with the marketing department of any other manufacturer that bothers to look) know the emphasis on SINAD here is a race they will lose, so a review is not going to help them sell product. So why offer products for review, and why make changes that might satiate ASR when they can't "fix" their glaring SINAD "issue"? But it wouldn't take much of a refocus to change that equation. As my wife likes to say, it's a matter of tone. Here's a revised conclusion based on the same set of data, with a slightly different tone and take:

"Cambridge have usefully removed 5dB of noise over the prior iteration. This is now one of the cleanest linear power supply integrated amplifiers I have ever tested. The linear power supply will likely offer long-term reliability, and offers some useful headroom which many switching supply products do not. For those who are seeking this product mix, this is a likely to be a satisfactory and recommended combination. It is unfortunate that a phono stage is not integrated, however Cambridge does offer a very good separate phono stage which I have also reviewed favorably. That said, the pre-amp outputs, while remaining quiet and with a relatively high SNR, will have some mild distortion added over 1.6V output due to likely clipping of the internal amplifier allowing distortion back into the pre-amp stage, so gain matching may be important if you plan to use this with an external amplifier. If you need a full 2V and that mild amount of distortion on the last 3dB is unacceptable to you, or you desire something with a much higher SINAD, separates may be a better option."

That is still completely true, objective, and fair. It is not misleading in the slightest. Yet, it gets the point across without insulting the manufacturer and flaming them for a minor issue, and saying their product is "not recommended" and they they appear to have "done nothing" despite now being among the better ones in the class for those looking for something like this. With that approach, I think Cambridge and other manufacturers would both be more inclined to care about your feedback, and possibly even offer a review sample. That's good for everyone. This review is just proof they may as well not care at all. They take noise out, and get nothing for it because of an edge case on preouts. It just seems counterproductive to me.

Please don't take this as criticism. I intend it to be constructive because I do care that manufacturers make improvements to products based on solid engineering and science. Cambridge did some of that here. They pulled noise out of a product with a linear supply, which is not easy to do. Yet, they get no credit for that. Giving manufacturers credit where credit is due and not unduly chastising them for edge cases is, in my view, key to building credibility and influence with them, which I think helps the cause.
I should agree with you, since I defended the idea of a linear power supply against an SMPS for reasons of reliability and production cost for equal quality, number of power supply rails and reliability, and I defended the idea that a sinad of 103 dB at 1.6 volts for the unbalanced pre out was relevant because of the sensitivity of the hifi amplifiers sold (and thanks to Restorer John for his list of amps proving this), but at the same time, even though I have the greatest respect for Cambridge Audio. Some of whose products have in the past enlightened me about the audibility of things (I went resolutely over to the objectivist clan when I couldn't tell their Dac Magic (first vertical version from over 15 years ago) from a Weiss 24/96. .. ) and others annoyed (the repeated bugs of their first HC and Streamer integrated units, also a long time ago) and even frankly annoyed (the mediocrity of their Azur amps, with that ridiculous cover boasting the qualities of an ordinary transformer stashed underneath), but I'm sorry, and Amir is undoubtedly right, rather than indulging in the audiophile subjecitivist idiocy of writing legends about the "colossale" importance sound according to the location of a component on the circuit (you'd think you were listening to the legends about Naim's historic boss...), Cambridge Audio would have done better. ...).

Cambridge Audio would have done better to ensure that the amplifier didn't throw distortion into the preamp-buffer stage above 1.6 volts, in order to make this output, which I've already pointed out is fully functional in practice with a lot of amplifiers. How can we do this? Either by using the good old family jumper, or by taking better care of something on the circuit, as these outputs can also feed subwoofers... They were warned, they knew it and they could do something about it... Instead, they chose to feed the audiophile legend...

PS: I wonder how the amplifier can saturate if no speakers are connected: doesn't the amp see an infinite impedance and therefore deliver no power? I'm not expert enough to know. So if you can explain.
 
Still have the companion DC-300 power amp?

Oh, I dunno. Are NE5532s going for more than a buck these days?
I do have a particular DC300Amk1.5 (satin finish and IOC lights) on my bucket list, but I reckon I'll be back active by the time it comes up if ever it does (it's in a small vintage static collection and hardly ever used).


In this Cambridge case, they didn't *need* to alter the gain structure as they no doubt felt they don't need to - and let's face it (and I sincerely mean no disrespect here), how many potential owners of this amp know or care about ASR, let alone this site's very strict protocols for levels. No doubt Stereophile tests would have settled on 1.5V or so output and left it there - maybe?



P.S. Having read their bull***t prose posted by Amir above and by an engineer I think to boot, it's obvious the market they're pandering to - and it ain't ours, sadly!
 
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