Perhaps the best thing to do is not to speculate about other's motivations. Personally, I don't find it all that offensive, but I'm not very easy to offend! 
Really, though, let's get back to the technical. What I haven't seen anyone say a word about is whether my impression that when looked at as an amplifier, this actually is a very fine product with exemplary measurements. I am curious whether I am missing something here. To me, this may well be a product I actually spent some time looking for at one point, an implementation of Douglas Self's "blameless" amplifier. To get to where Cambridge did with this thing, they had to pay close attention to keeping the circuit very clean, and minimizing distortions along the way, versus just dumping feedback at the problem.
Let's compare this, for a bit, to the Yamaha A-S701. There were a few reports about people dumping the Cambridge for the Yamaha after some of these reviews dropped, although that may have been after the since-deleted initial review of the CXA81. Were they right to do so? Let's explore the IMD measurements:
This test is rarely performed by ASR, and was not here, so we don't have one for the Cambridge, and thus we can't make an "apples to apples" comparison. But, we do have one from Stereophile for the MkI version. We'll use that:
The powers levels are different, so that's not ideal, but what we can see is that at 5W into 19+20kHz the Yamaha has a higher 1kHz difference component than the Cambridge does at 25W into 8 ohms. To be clear, both of these are exemplary results. Still, is there anything we might be able to learn about these amplifiers from the results?
This test, of course, is the CCIF test. The Cabot paper provides an introduction to what it shows. Let's look first at 1kHz. Even putting out 25W, it is absent on the Cambridge. While a higher load, it is present on the Yamaha at 95dB, or at least below -110dB. Cabot tells us that "Even order or asymmetrical distortions produce the low difference frequency components while the odd order or symmetrical nonlinearities produce the components near the input signals." So the Cambridge has potentially eviscerated even order distortion almost entirely. That's quite promising. So far as odd order effects, it's a little harder to tell which is better since we have different power levels and impedances. Both are very low. Again, from the 15kHz results, we expected that. It's also somewhat comforting that when fed a mix of closely spaced tones, the amp is likely not spewing out distortion lower in the frequency band.
What else can we tease out? Well, how about crossover distortion? CCIF 2nd order (1kHz) is very insensitive for that, so the lack of the 1kHz difference component doesn't answer that. 3rd order tells us that (sidebands). There are some sidebands. So there could be some. The other problem we have is that as power increases, this form of distortion goes down, and we have a 25W test. True, 20kHz is very sensitive for this, but it's very sensitive for everything. What we're interested in is what the amplifier might do at low levels and high levels when fed music. Will it have crossover distortion at low levels? Will it do something bad at high levels? I don't know that we have enough information to tell us that. We really need swept tests to get into the nitty gritty, or scope readings.
But remember, we do have this odd anomaly that the 15kHz distortion drops as the output increases. That suggests high frequency distortion flattens off, even though the signal is ramping up. That's just a really nice indicator that the amp will be very clean at high powers, too. Unfortunately, we may not be able to tease out much more about low numbers, since the curve are buried in the noise. Of course, we can see that unlike the Yamaha (again, both have negligible levels) there are no IMD spikes poking out of the noise floor. So we don't have the symptom of a nonlinear amplifier that was "fixed" with a hefty (but not large enough) dose of feedback. Again, that's another good sign of a very, very tidy circuit.
Really, though, let's get back to the technical. What I haven't seen anyone say a word about is whether my impression that when looked at as an amplifier, this actually is a very fine product with exemplary measurements. I am curious whether I am missing something here. To me, this may well be a product I actually spent some time looking for at one point, an implementation of Douglas Self's "blameless" amplifier. To get to where Cambridge did with this thing, they had to pay close attention to keeping the circuit very clean, and minimizing distortions along the way, versus just dumping feedback at the problem.
Let's compare this, for a bit, to the Yamaha A-S701. There were a few reports about people dumping the Cambridge for the Yamaha after some of these reviews dropped, although that may have been after the since-deleted initial review of the CXA81. Were they right to do so? Let's explore the IMD measurements:
This test is rarely performed by ASR, and was not here, so we don't have one for the Cambridge, and thus we can't make an "apples to apples" comparison. But, we do have one from Stereophile for the MkI version. We'll use that:
The powers levels are different, so that's not ideal, but what we can see is that at 5W into 19+20kHz the Yamaha has a higher 1kHz difference component than the Cambridge does at 25W into 8 ohms. To be clear, both of these are exemplary results. Still, is there anything we might be able to learn about these amplifiers from the results?
This test, of course, is the CCIF test. The Cabot paper provides an introduction to what it shows. Let's look first at 1kHz. Even putting out 25W, it is absent on the Cambridge. While a higher load, it is present on the Yamaha at 95dB, or at least below -110dB. Cabot tells us that "Even order or asymmetrical distortions produce the low difference frequency components while the odd order or symmetrical nonlinearities produce the components near the input signals." So the Cambridge has potentially eviscerated even order distortion almost entirely. That's quite promising. So far as odd order effects, it's a little harder to tell which is better since we have different power levels and impedances. Both are very low. Again, from the 15kHz results, we expected that. It's also somewhat comforting that when fed a mix of closely spaced tones, the amp is likely not spewing out distortion lower in the frequency band.
What else can we tease out? Well, how about crossover distortion? CCIF 2nd order (1kHz) is very insensitive for that, so the lack of the 1kHz difference component doesn't answer that. 3rd order tells us that (sidebands). There are some sidebands. So there could be some. The other problem we have is that as power increases, this form of distortion goes down, and we have a 25W test. True, 20kHz is very sensitive for this, but it's very sensitive for everything. What we're interested in is what the amplifier might do at low levels and high levels when fed music. Will it have crossover distortion at low levels? Will it do something bad at high levels? I don't know that we have enough information to tell us that. We really need swept tests to get into the nitty gritty, or scope readings.
But remember, we do have this odd anomaly that the 15kHz distortion drops as the output increases. That suggests high frequency distortion flattens off, even though the signal is ramping up. That's just a really nice indicator that the amp will be very clean at high powers, too. Unfortunately, we may not be able to tease out much more about low numbers, since the curve are buried in the noise. Of course, we can see that unlike the Yamaha (again, both have negligible levels) there are no IMD spikes poking out of the noise floor. So we don't have the symptom of a nonlinear amplifier that was "fixed" with a hefty (but not large enough) dose of feedback. Again, that's another good sign of a very, very tidy circuit.
