Hello Everyone,
This is a review and detailed measurements of the Cambridge Audio Azur 640C V2 CD Player and Transport.
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The ASR member
@Thomas_A already did a mini-review of
the same player, some time ago, and I was interested to try it by myself too, but it's not easy to find one at a decent price. Also, the one of
@Thomas_A was a more recent revision 7, while mine is a revision 3, so that might be interesting to see potential differences.
Azur 604C V2 - Presentation
This version 2 uses two DACs WM8740 from Wolfson, instead of one in the 640C V1. This DAC was used in few players, almost all from the UK (Arcam, Rega, Cambridge, Linn, Rotel,..), and it's the one used in the
Orpheus Zero from Switzerland too. And basically, that is the reason why I got interested by this player, to see if it repeats the same performances at a much more reasonable price than the Orpheus, and also if it took benefit of two DACs used in mono-mode instead of one.
The Azur 640C V2 was available from 2008(?) and I don't know until when.
I like the look of this CD Player, almost high-end by its external finish. I did not take other pictures, but its sides are not stupidly flat, they are shaped in a double wave which provide a sense of luxury. The box is all metal with an aluminum front face.
It is a CD Player only, using a Sanyo SF-P101N drive that I was interested to test too.
On the back, we get all we need:
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Analog RCA outputs and SPDIF + Toslink, I'm not really asking for more.
The published specifications are the below:
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Note that a THD (+N) of 0.0005% @-10dBFS is an impossibility with the Audio CD, because of the noise floor limit (due to 16bits decimation), so I guess this is a typo, with one 0 too many (and to cut it short, I measured 0.0034% of THD+N @-9dBFS). That said, talking THD only (noise excluded), I saw 0.0003% @-9dBFS, but Cambridge Audio should make it clearer if they included noise or not in their specs, but by default we assume it is THD+N.
Same with the IMD CCIF (19k+20k), <0.0008% can only be without noise (I measured 0.00056% in that case).
Ok, let's have a look at the internals:
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The servo/decoding board on the left is almost entirely hidden below a copper plated cage. The service manual reveals the main component is a Toshiba TC9462FG that decodes. interpolates, performs error correction (dual C1 and quadruple C2) and even includes a 1bit DAC with necessary filtering and interpolator (not in use here, of course). The drive is a Sanyo SF-P101N.
You can see that mine has copper plated cover for the toroidal transformer which was dropped from Revision 6 and 7 of this CD Player.
Let's have a look at the main board:
View attachment 523604
The two Wolfson DACs are under the board, we don't see them. Below the copper plated screening can, there is an XTAL of 50ppm precision, understand a "standard" one (it is labelled "Low-Jitter Master Clock").
User Experience
I now like to share some subjective data about my interaction with a device.
The buttons on the front are not so reactive and it seems to be a recurring issue with this generation of Cambridge Audio devices. I can't verify that but mine has sometimes difficulties. Besides that little issue, the drive is pleasantly fast, nearly as fast a the good old KSS laser heads from Sony when it comes to skip on or multiple tracks and FFW/REW, and I like that a lot.
The display is simple and large enough to be seen from a good distance, that is nice. The Servo chip is supposed to read text CDs, but I didn't test that.
To my surprise, the Azur 640C V2
does not apply de-emphasis when required, despite fact that the Wolfson DAC offers that function, go figure. I did not test if it is gapless playback, but I'll assume it is (I'll try to test that later on).
Azur 640C V2 - Measurements (Analog outputs)
All measurements performed with an E1DA Cosmos ADCiso (grade 0), and the Cosmos Scaler (100kohms from unbalanced input) for analog outputs, and a Motu UltraLite Mk5 for digital.
I am now consistent with my specific measurements for CD Players, as I described them in the post “
More than we hear”, and as I reported them for the
SMSL PL-200 review. I used the commercial version of my
Audio Technical CD for all measurements. Over time, this will help comparing the devices I reviewed.
The 640C V2 outputs a higher than usual 2.301Vrms from left channel, and 2.292V from right channel (0.03dB less). This is a good 1.2dBu more than from the standard 2Vrms, which is enough to make this one "sound better" than most of the competitors, because it plays louder.
Phase is dead flat, and unbalanced outputs respect absolute polarity.
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As usual, let's start with my standard 999.91Hz sine @0dBFS (without dither) from the
Test CD (RCA out):
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These results are the same that
@Thomas_A reported. The only difference is that the above is without dither. We get the same little interaction between mains and the fundamental (you can see the low level spikes around it), it is without audible consequences. A THD+N of -97dB means 0.0014%, by the way
The level of distortion is very low and the results shown in the dashboard are quasi-identical to those of the
Orpheus Zero which uses only one DAC.
Let's try the same at -6dBFS:
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Again same results as
@Thomas_A only difference being no dither here, so we see a little more of the PS leakage (at very low level -125dBr here).
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Talking Power Supply, I usually have a look at it, and here it is very limited, even if I zoom and run a punishing 512k FFT length:
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This view shows very small leakage (-130dBr) of the mains and harmonics (50Hz in Europe), but better shows the interaction with the fundamental at full scale, up to -120dBr (800H, 900Hz, 950Hz). But all of that will remain hidden to your ears.
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Next is the bandwidth:
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This is very flat, even flatter than the Orpheus despite the same DAC being used (more on that below). You can see the very small 0.03dB channel imbalance of no importance and very good for two separated DACs in use here.
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Let's have a look at the behavior of the oversampling filter beyond 20kHz:
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I used on purpose the same colors as with the Orpheus, for you to compare, if you wish. Both players use the sharp filter of the Wolfson DAC and it performs exactly the same way (-90dB attenuation, or so, as per specs). That said, the Azur generates less noise beyond 45kHz and I suppose this due to the utilisation of two DACs in mono mode. Overall, the attenuation of unwanted conversion noise is better with the Azur 640C V2.
Note that the AES test tones are also better attenuated too, as a consequence, which is to appreciate.
I'll talk about it later, but the IMD from the AES test reveals much less distortion from the Azur than from the Orpheus, you can already see that if you compare the two graphs.
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Let's have a look at the multitone test that a lot of you like very much:
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Nailed, best is class trace for a CD Player.
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Oh yes, the jitter test:
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Nearly absent. We get again that interaction around the fundamental which generated two very small and very close spikes. No impact of course, and actually a little better than the
Orpheus.
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Started with the
Teac VRDS-20 review, and on your request + support to get it done (more
here), I'm adding now an "intersample-overs" test which intends to identify the behavior of the digital filtering and DAC when it come to process near clipping signals. Because of the oversampling, there might be interpolated data that go above 0dBFS and would saturate (clip) the DAC and therefore the output. And this effect shows through distorsion (THD+N measurement up to 96kHz):
The overall results of the Cambridge Audio Azur 640C V2 are best in class, a little above the Orpheus and the SMSL PL200. This is very good resistance to ISO without requiring a manual digital volume attenuation. This was clearly an advantage of the Wolfson DAC, few dB sacrifice on max resolution (probably) to offer very good resistance to intersample overs in its interpolator.
This means we get very close to the desired 3dB headroom to prevent generation distortion from intersample overs. This to appreciate since
many CD Masters are recorded too hot.
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Let's continue with the good old 3DC measurement that Stereophile was often using as a proof of low noise DAC. It is from an
undithered 997Hz sine at -90.31dBFS. With 16bits, the signal should appear (on a scope) as the 3DC levels of the smallest symmetrical sign magnitude digital signal:
View attachment 523621
No surprise that we get a very good trace on that test which demonstrates a very good linearity of that conversion and very low level of noise, as with the
Orpheus.
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Other measurements (not shown):
- IMD AES-17 DFD "Analog" (18kHz & 20kHz 1:1) : -98.3dB
- IMD AES-17 DFD "Digital" (17'987Hz & 19'997Hz 1:1) : -105.4dB
- IMD AES-17 MD (41Hz & 7993Hz 4:1): -99dB
- IMD DIN (250Hz & 8kHz 4:1) : -92.2dB
- IMD CCIF (19kHz & 20kHz 1:1) : -105.4dB
- IMD SMPTE (60Hz & 17kHz 1:4) : -92.1dB
- IMD TDFD Bass (41Hz & 89Hz 1:1) : -109dB
- IMD TDFD (13'58Hz & 19841Hz 1:1) : -110.4dB
- Dynamic Range : 98.7dB (without dither @-60dBFS)
- Crosstalk: 100Hz (below -140dBr), 1kHz (below -140dBr), 10kHz (-118dBr)
- Pitch Error (GPSDO corrected) : 19'997.26Hz (19'997Hz requested) ie +13ppm
- Gapless playback : Yes
The IMD scores are very good, a little better than the Orpheus at high frequencies.
The Dynamic range is near the best that can be measured (unweighted) with the Audio CD.
Crosstalk was below what I can measure from the Audio CD at 100Hz and 1kHz, and a very low -118dBr at 10kHz (10dB more than the Orpheus).
Pitch error is a very small 13ppm (a little more again than the Orpheus).
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Last and not least, I like to run a THD vs Frequency sweep at -12dBFS as it shows how the conversion has evolved over time. I am currently using the beta version of REW and I discovered that this sweep gives better and more reliable results than before. I overlayed the results with the Orpheus, and look:
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The plot is at 1kHz and the legend shows the respective THD (no noise), the Azur 640C V2 beats the
Orpheus again, even though this makes no differences.
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As I did with the
Sony CDP-597, I add a "
max DAC resolution" measurement test. It is performed from a 999.91Hz sine @-12dBFS with shape dither (from Audacity). I restrict the THD+N span to 20Hz - 6kHz in REW not to account for the noise of the shape dither beyond 6kHz. I take the calculated ENOB and simply add 2bits to it (due to the -12dB attenuation, as 1bits=6dB). The potential maximum, when calculated from the digital WAV file, is 18.7bits under this test. A "transparent" DAC should achieve 18.7bits, ie 100% in this test.
Here are the results compared to others:
On this exercise, the Azur falls short of 0.1bit to equal the Orpheus and that is because of a little more low level noise which I've seen across the board with the Cambridge. That said we are talking on only 1dB difference here... This is anyways a very modern result that many other CD Players can only dream of.
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On demand from the community, I now add a "de-emphasis test" to verify that this flag is detected and the compliance with the expected de-emphasis curve.
Unfortunately this is not the case with the Cambridge Audio and I don't understand why since it is a feature of the DAC. I don't see a reason not to comply here.
Azur 640C V2 - Testing the drive
What would be good measurements if the drive would not properly read a slightly scratched CD, or one that was created at the limits of the norm? The below tests reply to these questions.
Here are the results:
| Test type | Technical test | Results |
| Variation of linear cutting velocity | From 1.20m/s to 1.40m/s | Pass |
| Variation of track pitch | From 1.5µm to 1.7µm | Pass |
| Combined variations of track pitch and velocity | From 1.20m/s & 1.5µm to 1.40m/s & 1.7µm | Pass |
| HF detection (asymmetry pitch/flat ratio) | Variation from 2% to 18% | Pass |
| Dropouts resistance | From 0.05mm (0.038ms) to 4mm (3.080ms) | 1mm |
| Combined dropouts and smallest pitch | From 1.5µm & 1mm to 1.5µm & 2.4mm | 1mm |
| Successive dropouts | From 2x0.1mm to 2x3mm | 1mm |
Same results as with the Orpheus with a different drive and Servo. And same comment: I must admit I am a little disappointed by the above, for a modern drive. I guess this is the price to pay for the speed. This in line with many super fast Sony KSS laser heads though.
Note that if you have CDs in good condition, the above is more than good enough.
Azur 640C V2 - Digital output
Ok, so we get a very CD player here. And to expect better from a modern DAC, we need a perfect digital output. So let's test that.
This is my standard 999.91Hz @0dBFS (no dither):
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This is the same as the original WAV file that was used to create the CD track.
The 3DC test is nailed too, of course:
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My ultimate proof of "perfect" digital output is when I reuse the intersample overs test at 5512.50Hz, with a phase shift of 67.5°, like I did for the
TASCAM CD-200 review. This signal generates an overshoot of +0.69dB. And so, if the signal would be modified before being sent (by an ASRC for instance), it would show either a reduction of amplitude or we'd see some sort of saturation/increase of noise/distorsion. So here we go with the Azure via the Coax out:
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No distortion and the dashboard shows +0.69dBFS as expected. No ASRC on the digital path here. SNR is only 95.5dB because there is rectangle dither in this test file (consuming half a bit of resolution).
So we get a "perfect" transport on top.
Conclusion
For a near 20 years old CD Player, we get very close to best in class results.
I was really interested to see what I could get with two Wolfson WM8740 compared to one in the much more expensive Orpheus Zero. It doesn’t make a real difference, but at the end of the day, the value for money is much higher.
I don't know about the reliability of this CD Player, but this one still spins very well
And as far as I know, what I witnessed here is the definition of a high end CD Player.
I hope you enjoyed the review and I wish you a happy weekend!
