Xps2 dr on cdx2.2 or ndac

My current system is nac252, supercap, cdx2.2, ndac, nap300 and xps2dr with super lumina cables

My question is this, should I put the xps2 dr on the cdx2.2 or on the ndac for the best sound?

If you chose the nDAC to upgrade your transport you should already have your answer.

If you’re running the CDX2 digital to the DAC then put it on the DAC.

Try both, or three ways actually.
Psu on dac
Psu on cdp digital into dac
Psu in cdp analogue into amp. I.e. no external dac.

Also what spdif cable will you use?

Please report back and tell us which you thought was better and why.

Exactly this. No right answer on these things. Only your ears.

Although ultimately preference is subjective, technically the XPS2 on the NDAC provides the best powersupply provision.
Adding the XPS2 on the NDAC splits the NDAC powersupply into two… a bit like the NDS, CD555 and ND555 are capable of.
The analogue circuitry is powered by the external XPS2, and the digital circuitry is then powered by the NDAC native inbuilt PSU… so you have full separation between digital and analogue circuitry with the two power supplies feeding the NDAC.

Using the XPS2 on the CDX2 simply replaces the native inbuilt powersupply with a lower impedance external powersupply… completely bypassing and effectively disabling the CDX2 inbuilt powersupply

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With the Ndac the XPS2 powers both analogue circuits and digital circuits (Dac digital circuits and the clock). The onboard power supply feeds other digital circuits.

I am not sure you have that quite right. The external PSU powers the master clock analogue and analogue stages and converter circuitry. The clock oscillator is coupled into the digital circuitry through the iCoupler, but crucially is powered within the analogue circuitry demarcation. The critical digital signal chain including through the SHARC and BlackFin DSP processors are powered by the Naim DAC PSU when the analogue element is powered by the XPS2.

This diagram from Naim illustrates it either side of the analogue/digital dotted line.


You’ve actually just repeated everything I said (in more detail) and added a misleading diagram. (Placing a digital component on the analogue side of an isolator doesn’t turn it into an analogue component). :grinning:

Just to clarify what is actually going on inside the Ndac, I whipped off the lid and took a few photos. The regulators shown in the photo are all powered from the external PSU, as I indicated in my previous post these include the Dac digital circuits and the clock.

There is no digital component on the analogue side I can see, curious to what you might be referring to… unless you are referring to the analogue converters themselves? But clearly they are on the analogue side… but yes it has an i2S input… but the point of a converter is it turns a serial stream into an analogue current.

The master clock is based around a Colpitts oscillator resonated by a high precision crystal, producing a sine wave which is then shaped, the analogue converters are a pair of pcm1704K devices, and the i2V and analogue filters are… analogue…

I actually think the diagram was very informative when I owned my Naim DAC.

But anyway as I say my point is the internal PSU drives the digital circuitry, and the external PSU drives the ‘analogue side’ or analogue circuitry which Naim state is the master clock, converters and analogue filters, and the coupling point between the digital and analogue side is via the iCoupler digital isolator… nice and simple and provides good separation as the white paper explains and in practice really lifts the performance. :grinning:

Ndac Digital Circuits

Exactly… so we are all clear then… external PSU for analogue circuitry side of digital isolator inc converters and Colpitts master clock, and internal PSU digital side of digital isolator for digital circuitry inc digital oversampling and reconstruction filters. :kissing_smiling_eyes:

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