Dear ASR community
Firstly, thank you to Amir for listening to us and agreeing to do a re-test of our CXA81.
When the original test was published a couple of months ago we were part devastated and part confused. When his first review landed Amir didn’t know us as a company, and his findings and suggestions made Cambridge Audio come across as a "quick and dirty" company that knocks out products designed by people who don’t know what they are doing. Nothing could be further from the truth. The engineers are responsible for every PCB, line of software code and product design detail in our CXA81 are all UK-based and pride themselves on their craft, taking personal responsibility for their work, individually and as a team. They all work on products across our range, including several that have won great praise in previous tests by Amir and others in the ASR community, and they are fastidious – some would say fanatical – about what they do.
If we were a bigger, more “corporate” business it would be normal to pass the job of handling this off to someone in a comms or marketing department, however Cambridge Audio, and I, aren’t like that. My team and I have a deep connection with our business, our brand and the products we design. Our products take years to create and we take great pride in what we do. They are not churned out in a cookie-cutter process that lacks heart, we consider every detail end to end and spend many months hand picking components, comparing to competitor products, tuning, fine tuning and listening. So we were naturally upset to read Amir’s original review, knowing that something was very wrong.
Of course we’re only human, so let’s not pretend we’re perfect and don’t drop the odd ball, but with CXA81 I’ll do my best today to reassure you we haven’t. When it comes to our product, we really do try hard to make it as good as we possibly can, and whatever you may have thought about us reading Amir’s previous assessment, please give us a second chance and get to know us better by reading both this and Amir’s second test.
So how did this go so wrong the first time round, and why haven’t we got involved in the discussion here sooner?
Firstly, we do not believe there was anything at fault with the first unit on test. The distortion issues reported in the original test are clearly down to one main reason.
- Noise introduced by external devices in the test setup (we have tested over 20 units ourselves, and have replicated how this could have happened, with data to back it up). To elaborate on this in more detail, we have found that some computers create a noise differential that conducts noise between USB port grounds, the computer upstream connected to CXA81 via USB input, the APx balanced outputs upstream connected to CXA81 balanced input via XLR cables, and the APx connected to the computer via USB, a copper conducted audio noise loop is created and can add approximately 20db of low frequency noise.
Only a few types of products with such a feature set can be connected in such a way (which eliminates most standalone DAC products). This particular low frequency noise is only added to the audio due to the addition of the test/measurement equipment that would never be seen by any normal user set up.
Also, after extensive testing on our 20+ different CXA81’s, we can confidently say that the extra noise is added through the test set up and not created by the product. It is not possible for the CXA81 to create the low frequency noise shape internally. Even if there was the potential for there to be burst noise from a faulty component in the CXA81 (very unlikely in any case), the low frequency noise shape would be very different between the left and right channels. Also, there is no capacitance or mutual inductance large enough in the CXA81 or the setup for the low frequency noise to couple into the CXA81. The low frequency noise can only be conducted through cables in the setup.
- We also noticed that the correct USB Cambridge Audio driver was not being used and no effort was made to improve the performance by changing the grounding switch on the rear panel. Although, this had no bearing on the addition of noise.
It serves no purpose to repeat Amir’s own words on this, which I believe largely vindicate the above.
Another area of the first review relates to distortion measurements taken when a 2V signal is taken from the pre-out unbalanced RCA connectors. 2V is Amir’s test standard and may be the line-level standard, but it is not a level that is typical of that used when such pre-out sockets are connected to one of our power amplifiers, or another in a similar class. Amir as we all know is effectively testing CXA81 as a stand-alone DAC, whereas we all know it is designed to be used as an integrated amp which includes an attenuation stage in its signal path. The result is that Amir pushed the level from these jacks up to one higher than it was designed for. When, at our request, he subsequently tested output at 1.5V (a perfectly adequate and ideal level to drive one of our power amps, or those by other brands) the THD is at a level you'd expect from a quality brand like Cambridge Audio.
Those with a CXA81 themselves, or who may considering buying a CXA81 or anything Cambridge Audio, should be reassured that in a normal hi-fi system or set up, whatever showed on those original graphs will not be manifesting when playing music.
We know some of you who commented in the original review post were dismissive of the positive magazine reviews we have received as a result of Amir's original "findings". All I can say is that those posting those negative comments did so on the basis of what they read and not from first-hand experience listening and testing a CXA81 in front of them. Hopefully Amir's own words, his re-test and my message here convinced those now that this product is not the duffer you were led to believe. Jon Atkinson’s Stereophile review also backs this up.
Amir was also critical about some of the things we did with user experience, as well as some of the words used on our website. Small stuff, but we sweat the small stuff, so let’s cover those off too, and not just sweep them under the carpet..
The UX comments surprised us as no one before has given us such feedback (and we’ve enjoyed a lot of reviews). But we respect his opinion and are never too big or proud to take on board feedback, to learn how we can do better. We consciously haven’t put a display on the front of CXA81 because we simply don’t see a need, or a real customer benefit given this is a high-performance value-orientated integrated amp with an onboard DAC, not a standalone DAC. We also wanted to keep button count down, thus dual-purposing a couple of input buttons. Roon labelling follows Roon’s rules which we have little/no influence over.
Amir picked up on the statement that claimed CXA81 was “designed and specified without compromise”, of course at this price level there has to be some element of compromise, so we’ve amended these words.
On the latter point (why didn't we get involved in the conversation on the previous test comments/forum), we took an initial decision to see how things panned out whilst also fully investigating and verifying internally what we believed had gone wrong. I reached out to Amir and over a number of days we saw a meeting of minds and a mutual respect. But the whole process took quite some days and by that time what was being said on the forum was hard to respond to and frankly toxic at times, making it hard for us to respond without Amir or a third party test company verifying our findings. Amir agreed to listen to us and re-test, and myself and the engineers who designed CXA81 had a Zoom call with Amir to talk things over and get to the root of the problems experienced by Amir.
I hope this helps, and shows you the care and attention we at Cambridge Audio put into making genuine high quality audio products that are designed to offer value and performance and delight our listeners all over the world.
Best regards
James Johnson-Flint
CEO
Cambridge Audio