Cambridge Audio Azur 640C V2 Review (CD Player)

[LuckyNat]

-3dB is what it takes with many recent masters, especially pop and rock music but would not be enough with some. I’d still go for that, personally.

And we’d need to measure this box to see if it’s otherwise transparent

That would be interesting (to measure the 618) ..

 

[Koeitje]

I had a 540C V2.

 

[NTTY]

Here you go with the NAD C540 review, to compare with this very nice Azur (if you ask me).

 

[Pauper]

I’ve just bought a mint Azur 650c for £65 and it sounds marvellous!

 

[scott_arm]

I have one of these boxed up in my closet. It stopped reading discs. Maybe I should look into fixing it.

 

[ddaudio]

Thank you for this review. Very interesting.
I own a 840C that has (supposedly) better DAC with built-in upsampling circuitry.
It can be used also as DAC thanks to SPDIF/Toslink input.
Do you think you will have the opportunity to test this model as well?

Thank you again!

I have an 840C and am attempting to test it using the @NTTY CD and methodology. It certainly looks good up to now.

Key blurb (from the manual):

• Anagram Technologies ATFTM (Adaptive Time Filtering) upsampling process... This system intelligently interpolates 16 bit/44.1kHz CD (or other) data to 24bit/384kHz through the use of a 32 bit Analog Devices Black Fin DSP (Digital Signal Processor)
• The ATF system applies sophisticated polynomial curve fitting interpolation and incorporates a time domain model which allows data buffering and re-clocking almost completely eradicating digital jitter.
• Because the audio data rate is so high aliasing artefacts are moved way above audible frequencies allowing us to use a low order 2 pole linear-phase Bessel filter on the output for constant group delay and minimal phase shift.
• Two very high quality Analog Devices AD1955 24 bit DACs are used in dual differential mode.

It also has digital inputs and outputs. The digital outputs can be passthrough or upsampled to 48/96/192 at 16, 20 or 24 bits, with or without dither. Some potential for measurements there!

Note that my interface is set to minimum gain which loses about 6dB in level (if I turn up the pre-ADC gain, I lose SINAD). I guess this is OK as I'm digitizing at 24/192? Also, the Topping E2x2 interface ADC may be a limiting factor with some measurements, Amir found its ADC SINAD to be 110dB and here I'm using it with unbalanced input nominal only 2V. I did measure its ADC SINAD at 106.3dB (20hz to 20khz) under those conditions (using a DAC with an Amir-measured SINAD of 120dB).

The 840C has balanced outputs but I don't have the necessary cable.

Jitter (as per the blurb, it certainly seems to have been eradicated):

Filter:

 

[NTTY]

You get very good results! If you increase the gain of the Topping when measuring the Azur at 0dBFS, what is the resulting THD+N? Same, isn’t it?
But anyways, even so you’re good for CD players measurements, since it’s the max the format is capable of

 

[ddaudio]

You get very good results! If you increase the gain of the Topping when measuring the Azur at 0dBFS, what is the resulting THD+N? Same, isn’t it?
But anyways, even so you’re good for CD players measurements, since it’s the max the format is capable of

The THD+N increases by 1.3dB. Looks to be mostly extra 2nd, 3rd and 5th harmonic distortion.

 

[ddaudio]

I've fixed it. Being a Linux user, I had to start up a Windows VM and use the Topping control software to apply +5dB digital gain to the interface, leaving the pre-ADC analog gain at minimum. (+6 ran into clipping). The software allows the settings to be loaded into the interface, so continue to apply under Linux.

 

[NTTY]

Nice!
If you plan to test different CD players, you might want to keep some headroom with digital gain (like 4dB, it obviously does not degrade measurements), and adjust the last few dbs with the analog gain, in case it makes a difference.

 

[BobbyTimmons]

The inclusion of both an optical and coax output is a nice touch.