Cambridge CXA81 MKII Amplifier Review

[vuittion]

Looks like a total car crash. Maybe we can get someone from Cambridge to defend it.

 

[Koeitje]

It could be a budget oriented design decision. Why pay more for a SOTA DAC when its performance is swamped in the power amp? Finally what counts is what comes out of the speakers.

I'm too lazy to look at the precise measures, but won't it reach 1.6V+ internally while feeding the power amp stage? Odds are that the DAC is dragging down the performance in that case.

Regardless, there is literally no excuse to not have it reach 2V. If it did with 103dB SINAD it would be more than good enough in my book. But its clear that Cambridge Audio didn't really care about performance.

Why is this 1.6 volt pre out output level a real problem?
If the output impedance is low and the power block it could be connected to has a sensitivity of 0.775 volts, or even 1.5 volts... it should work, right?
I really ask the question, because I often see audiophiles advocating the use of preamps delivering 10 volts and more... What is the use of such a gain in a preamp when the level of unbalanced sources is 2.1 volts these days? ?
I really ask the question

Not really the case for this amplifier because it has its own power amplifier, but when connecting to active speakers low output voltage can be an issue. I use a Fiio K7 for my powered speakers. It has a 2V output and I can almost max out the volume on the Fiio when I want to listen loud. A 1.6V output wouldn't be enough for me. I could increase the gain on my powered speakers, but in my case that comes with a lot more self noise and thus is not really an option.

 

[AudioSceptic]

They would have done better to make it as a stand-alone power amp IMO. Voted 'not terrible' but would have voted 'great' if it were just a power amp.

Maybe, but it would need a *lot* more power or be a *lot* cheaper as just a power amp. Compare with something like the Fosi V3 <https://archimago.blogspot.com/2024/08/part-ii-fosi-audio-v3-mono-amp-class-d.html>.

 

[AudioSceptic]

I'm too lazy to look at the precise measures, but won't it reach 1.6V+ internally while feeding the power amp stage? Odds are that the DAC is dragging down the performance in that case.

Regardless, there is literally no excuse to not have it reach 2V. If it did with 103dB SINAD it would be more than good enough in my book. But its clear that Cambridge Audio didn't really care about performance.


Not really the case for this amplifier because it has its own power amplifier, but when connecting to active speakers low output voltage can be an issue. I use a Fiio K7 for my powered speakers. It has a 2V output and I can almost max out the volume on the Fiio when I want to listen loud. A 1.6V output wouldn't be enough for me. I could increase the gain on my powered speakers, but in my case that comes with a lot more self noise and thus is not really an option.

1.6 is about 2 dB less than 2.0. Would that make such a big difference?

 

[Phorize]

Another example of a highly regarded English brand under performing. Can't help but feeling duped over many years by the HiFi magazines, who were glowing in their admiration for these brands.

For the same money you can have a minidsp Flex or WiiM front end, combined with a hypex power amp assembled by one of several competent manufacturers.

It must now be clear to even the most ardent "subjective" that the only way you can be assured of getting transparent and high performing gear is by measuring it. No ifs or buts.

Your work is invaluable Amir, thank you.

Edit: typo

Every major hifi brand has introduced mediocre products to the market and this one isn't objectively poor, it's just not good value. I also believe that CA produce a good performing amplifier, just at a high price. At the end of the day there are 2 types of brand 1) brands that reliably bring objectively good products to market (such as Kef) and 2) those that don't. The vast majority of hifi brands fit into the later category and most of those in category 1 are tiny companies.

 

[Haskil]

I'm too lazy to look at the precise measures, but won't it reach 1.6V+ internally while feeding the power amp stage? Odds are that the DAC is dragging down the performance in that case.

Regardless, there is literally no excuse to not have it reach 2V. If it did with 103dB SINAD it would be more than good enough in my book. But its clear that Cambridge Audio didn't really care about performance.


Not really the case for this amplifier because it has its own power amplifier, but when connecting to active speakers low output voltage can be an issue. I use a Fiio K7 for my powered speakers. It has a 2V output and I can almost max out the volume on the Fiio when I want to listen loud. A 1.6V output wouldn't be enough for me. I could increase the gain on my powered speakers, but in my case that comes with a lot more self noise and thus is not really an option.

that of course! But here we have a preamplifier-amplifier which has asymmetrical Pre out outputs made to possibly be connected to an amplification block therefore having asymmetrical inputs on RCA whose sensitivity is therefore generally between 0.776 volts and 1.5 volts. This 1.6 volt output will also be suitable for speakers with an unbalanced input and for the same reasons.
This output level of 1.6 volts allows them to reach their maximum level and it is therefore not a problem if we consider the class of a device which is not intended to be a premplifier driving monitors with balanced inputs and standardized sensitivity for that type of input.

If this Cambridge had balanced XLR outputs which had a level of 1.6 volts, on the other hand I would criticize it.

My question was rather why, even to power amps or powered speakers with an input sensitivity of less than 2 volts, so many audiophiles recommend preamps with a very high output level which actually forces them to decrease very significantly. their output level... which is not without posing problems sometimes when we only have the first centimeter of movement of the volume potentiometer available which, on top of that, then works at the start of the track.. . which is not the best...

 

[Phorize]

Looks like a total car crash. Maybe we can get someone from Cambridge to defend it.

Really, a total car crash? It's a mixed bag and not great value. Let's not get hysterical.

 

[johnbachel]

The primary issue with this appears to relate to one use case: feeding a power amplifier with the device. I suspect that most buyers use the integrated amplifier. In any case, I wonder if any of the reported numbers relate to audible performance defects.

 

[restorer-john]

that of course! But here we have a preamplifier-amplifier which has asymmetrical Pre out outputs made to possibly be connected to an amplification block therefore having asymmetrical inputs on RCA whose sensitivity is therefore generally between 0.776 volts and 1.5 volts. This 1.6 volt output will also be suitable for speakers with an unbalanced input and for the same reasons.
This output level of 1.6 volts allows them to reach their maximum level and it is therefore not a problem if we consider the class of a device which is not intended to be a premplifier driving monitors with balanced inputs and standardized sensitivity for that type of input.

If this Cambridge had balanced XLR outputs which had a level of 1.6 volts, on the other hand I would criticize it.

My question was rather why, even to power amps or powered speakers with an input sensitivity of less than 2 volts, so many audiophiles recommend preamps with a very high output level which actually forces them to decrease very significantly. their output level... which is not without posing problems sometimes when we only have the first centimeter of movement of the volume potentiometer available which, on top of that, then works at the start of the track.. . which is not the best...

There's nothing inherently wrong about a peak performance via the preamplifier outputs around 1.6V.

In fact, that's pretty much right in the perfect zone for RCA amplifier outputs and sensitivities for power amplifiers like forever. Most RCA (SE) power amplifiers were specified for between 1.0V to 1.5V for full rated output. Their preamp and power amp stages fit that perfectly. In fact, UK and EU sensitivities were at the lower end of that and still are.

Much of this outrage about output levels is coming from people who have never measured a single source at typical listening levels in their whole life, letalone considered or tested a system in its entirety from end to end for sensible gain staging with variable sources.

 

[Haskil]

Not even, John Bachel! Almost all high fidelity power amplifiers having an unbalanced input on RCA have an input sensitivity which will pose no problem at the output of this Cambridge whose 1.6 volt will deliver their maximum power to these amplifiers.

 

[Sokel]

Really, a total car crash? It's a mixed bag and not great value. Let's not get hysterical.

Yep.
17 bits for the DAC and 15-16 bits for the amp at the multitone tests shows the CD quality is not far,I would expect it to be as good as anything there.

Another good one is the EU respect limits for stand-by operation as Amir reports 0W,this seems like a neglected spec some times and lets not forget that it's even illegal to be more than 0.5W in EU.

Yes,one can get combos near or lower than this price range with objectively nicer measurable performance and for a little more the same reliability (this one has an advantage over the decades with its linear PSU) ,good overall record,ease of any interactions and possibly the chance to "listen" to it at brick and mortar reps.

There are meals for all I guess.

 

[Haskil]

There's nothing inherently wrong about a peak performance via the preamplifier outputs around 1.6V.

In fact, that's pretty much right in the perfect zone for RCA amplifier outputs and sensitivities for power amplifiers like forever. Most RCA (SE) power amplifiers were specified for between 1.0V to 1.5V for full rated output. Their preamp and power amp stages fit that perfectly. In fact, UK and EU sensitivities were at the lower end of that and still are.

Much of this outrage about output levels is coming from people who have never measured a single source at typical listening levels in their whole life, letalone considered or tested a system in its entirety from end to end for sensible gain staging with variable sources.

You reassure me! I was insulted copiously on a French forum because I made your speech. And when I talked about the earnings chain, it got worse! I'm always surprised to see that we make preamps that output 10 and even 20 volts, onto which we connect sources that are 2.1 volts! We work in attenuation, not in preamplification as in the era of LPs and the RIAA preamp, and even tuners and tape recorders whose output levels did not reach 2 volts!

 

[peng]

You want to know where the performance bottleneck is. And most people who buy a product like this are more likely in my opinion to use the onboard D/A than be buying another external DAC-in-a-box.

Testing through the preamp is the only option as Cambridge hasn't fitted a tape out.

Agreed 100%, that's why I don't want to buy such so called integrated amp, that is no better than an entry level AVR except they usually come with 2 channels, but lots AVR users somehow think those kind of integrated amps "sound better", that' silly, though obviously in some cases they might in fact sound better.

In this case, the SINAD performance bottleneck will most likely/mainly be the preamp section, based on the DAC IC's SINAD spec of 120 dB.

That means my $500 AVR+a $200 ext. DAC (via analog inputs and use direct mode) will likely perform just about the same if measured on Amir's bench, if I were in the USA I would send it in just to see..

 

[peng]

You reassure me! I was insulted copiously on a French forum because I made your speech. And when I talked about the earnings chain, it got worse! I'm always surprised to see that we make preamps that output 10 and even 20 volts, onto which we connect sources that are 2.1 volts! We work in attenuation, not in preamplification as in the era of LPs and the RIAA preamp, and even tuners and tape recorders whose output levels did not reach 2 volts!

You do get 2 V, or more, if you are fine with higher distortions+noise, in this case about 2 V. You can see that at >2 V, THD+N would increase further, but in much slower rate. I am not trying to defend this amp, and in fact I would much prefer to use an AVR for the same money but can do a lot more. So, even if I only use it for 2 channel, with subs, I would still take an AVR for the same money. I guess people like integrated amps because they thought an integrated is the next best thing to separates for "sound quality", that is mostly a myth debunked by plenty of ASR bench tests objectively measured results.

 

[DSJR]

I honestly don't see the value in measuring the DAC portion in an integrated Amp with the same expectations as the stand alone ones. no one in their right mind would buy an integrated Amp to use it as a DAC, prolly means you're not using 80 per cent of the features you pay for, plus you know the DAC design is matched to the Amp that is included. It's a bit like expecting active speakers to have an Amp output so you can use them to drive other speakers. bit silly to me.

Got to agree.

Also, I should say that while it's sad that the dac doesn't perform at 2V output (so a line driver/internal gain issue?), how many power amps expected to be used with a device like this (do Cambridge still make them, I haven't checked), have low input sensitivity (our Class D favourites almost certainly wouldn't be used with such a product). Most older style power amps are a volt or less sensitivity for full output, aren't they?

Having moaned above, I do appreciate that modern gear has moved on and a dac is expected these days to have 2V or so output on single ended and 4V or so balanced, but this box I suppose is somewhere between stand alone and an AV receiver? Looks frightening to me inside, I have to say.

Just pulled out the 851WP power amp spec. Looks to now be discontinued, but the input sensitivity for full output was 1.5V single ended and 3V (+1.5V, -1.5V) balanced

Cambridge Audio Azur 851W Power Amplifier

Delivering immense power and incredibly low distortion, the 851W power amplifier is perfectly matched to partner our 851E pre-amplifier and 851N network player; taking their pure signal and amplifying it with huge presence and authority."One of the most transparent, thrilling and richly...

www.cambridgeaudio.com

Newer model appears to be a smidgeon over 1V sensitivity for full output -

https://www.cambridgeaudio.com/gbr/en/products/hi-fi/edge/edge-w

Sorry fellas, I can't really see other bang up to date amps used with a box like this...

 

[capslock]

1.6 is about 2 dB less than 2.0. Would that make such a big difference?

What I suspect may be a problem (not sure that the amp gain structure really works this way):

Typically, the internal DAC will play whatever it is fed digitally. There is likely no digital attenuation ahead of the DAC. Downstream there will be an analog attenuator (typically a digitally controlled array of analog switches aka electronic potentiometer) and then the power stage.

The risk is that whenever the digital input signal contains close to full scale signal (true for about 90% of today's pop music recordings), it will go into clipping.

 

[DSJR]

You reassure me! I was insulted copiously on a French forum because I made your speech. And when I talked about the earnings chain, it got worse! I'm always surprised to see that we make preamps that output 10 and even 20 volts, onto which we connect sources that are 2.1 volts! We work in attenuation, not in preamplification as in the era of LPs and the RIAA preamp, and even tuners and tape recorders whose output levels did not reach 2 volts!

My fifty year old IC based preamp (Crown IC-150) claims up to 10V output single ended. The extensive manual (available online) strongly suggested pushing more signal through the pre-power interconnects and reducing the gain on the (usually matching Crown) power amps, keeping the preamp's 'volume control' well over halfway for reduced noise and distortion. Along with Ken Rockwell's suggestions and measurements, I updated the two op-amp chips which apparently reduces noise a few dB or so. With power amp gain pots set halfway, No idea how much my preamp is pushing out, but the channel tracking on the old s**t pot is better with control well advanced, so I'm fine while the thing still works.

 

[Limopard]

What a surprise: "ye olde Englishe traditionalists" also put their pants on one leg at a time. The device is quite competent and surely sounds transparent under most circumstances. But why there is a 4-digit price tag is beyond me. Clearly a "not terrible" for me.

 

[Haskil]

Le principal problème semble être lié à un cas d'utilisation : alimenter un amplificateur de puissance avec l'appareil. Je pense que la plupart des acheteurs utilisent l'amplificateur intégré. Dans tous les cas, je me demande si l'un des chiffres rapportés est lié à des défauts de performances audibles.

My fifty year old IC based preamp (Crown IC-150) claims up to 10V output single ended. The extensive manual (available online) strongly suggested pushing more signal through the pre-power interconnects and reducing the gain on the (usually matching Crown) power amps, keeping the preamp's 'volume control' well over halfway for reduced noise and distortion. Along with Ken Rockwell's suggestions and measurements, I updated the two op-amp chips which apparently reduces noise a few dB or so. With power amp gain pots set halfway, No idea how much my preamp is pushing out, but the channel tracking on the old s**t pot is better with control well advanced, so I'm fine while the thing still works.

It was a device designed to power amps with low input sensitivity. But when you have an amp whose input sensitivity is between 0.775 volts and 1.6 volts, very very common cases in domestic hifi in RCA connection, your preamp having 10 volts or more output becomes a problem for daily use. 'it has a track potentiometer: the level adjustment will be done at the very beginning of the potentiometer's travel and moving it by one millimeter will increase the level too much or decrease it too much, not to mention the imbalance between tracks which is often significant at the start of the track. And all this because of the line output level of the sources which is typically 2 volts...

 

[Billy Budapest]

What a surprise: "ye olde Englishe traditionalists" also put their pants on one leg at a time. The device is quite competent and surely sounds transparent under most circumstances. But why there is a 4-digit price tag is beyond me. Clearly a "not terrible" for me.

My thoughts exactly.