HDCD Light.

It must be controlled from the CDX2's DAC which you aren't using. 

How do you like the sound through the external DAC compared to the XPS powered CDX2?

It's great loads more detail top mid and bass is really firm

only been running it for 10 hours so I expect it to be the dogs nuts in a few weeks,

tonycurran1 posted:

hi just added a naim dac to my CDX2.2  connected to XPS now when I play a HDCD disc

the HDCD light does not flash

before fitting the dac the light used to be on when playing a HDCD

any advice please 

regards Tony.

As  the Yeti says, HDCD is specially encoded and processed Red Book PCM. It's designed to be playable from regular DSP/DACs with none of the HDCD attributes present, which will be the case with most external DACs or by using the CDPs internal HDCD enabled DSP to modify the PCM to bring out the HDCD attributes. When the DSP in the CDP detects the special little HDCD control messages in the RedBook PCM it lights the HDCD lamp and enables the HDCD processor.

Technically an offboard DAC could equally do this, as all the info needed is embedded in the PCM, but I am not aware of any that do.

Simon

Thanks Simon and Yeti.

I too have the CDX2/XPSDR/nDac combination. You can use dBpoweramp's music converter and add HDCD in the "add effects" option to restore the hi-res format (24/44.1). I've done this with a few HDCD's with good results. Although remember, the HD light does not illuminate for 24/44.1, only higher resolutions (e.g.24/96).

Interestingly, and as an aside, I have noticed that not all tracks on some HDCD's are cut in HDCD. Strange?  

Just to clarify my above post. I use dBpoweramp to rip the CD to my desktop PC, using the HDCD "add effects" option when ripping. The "converted" 24/44.1 file is then stored on my PC. I then copy the file to a USB stick and insert/play through the nDac. Latterly I have use Chromecast Audio through Plex Media Server to access these and other stored files. All seems to work very well from my perspective.

Hardbop, I believe dBPoweramp  uses either a public domain program, HDCD, or the MS Windows libraries that emulate in software most of the DSP functions of HDCD - and will create an approximated 18 bit file using 24 bit sample data if it detects a HDCD file. Its not bad - though I don't believe  as ideal of using the genuine Pacific Microsonics hardware DSP which contains all the HDCD functions as used in Naim CDPs.

If a particular PCM track on a CD does not contain the HDCD triggers, that means that track for what ever reason  was not mastered as HDCD - then it will not show as HDCD by the DSP and the light won't be illuminated.

S

Thanks Simon, illuminating as ever (no pun intended)!

Simon-in-Suffolk posted:

tonycurran1 posted:

hi just added a naim dac to my CDX2.2  connected to XPS now when I play a HDCD disc

the HDCD light does not flash

before fitting the dac the light used to be on when playing a HDCD

any advice please 

regards Tony.

As  the Yeti says, HDCD is specially encoded and processed Red Book PCM. It's designed to be playable from regular DSP/DACs with none of the HDCD attributes present, which will be the case with most external DACs or by using the CDPs internal HDCD enabled DSP to modify the PCM to bring out the HDCD attributes. When the DSP in the CDP detects the special little HDCD control messages in the RedBook PCM it lights the HDCD lamp and enables the HDCD processor.

Technically an offboard DAC could equally do this, as all the info needed is embedded in the PCM, but I am not aware of any that do.

Simon

There was a Pink Triangle one in the 90s that did, if I recall correctly.

Of course one of the disadvantages of using a Naim CDP with digital out to a DAC is that you lose the HDCD. This always drove me mad so I sold my dig out Naim CDP.

I have a rather treasured collection of hard-to-find Joni M albums on HDCD....

Salmon Dave posted:

Simon-in-Suffolk posted:

Technically an offboard DAC could equally do this, as all the info needed is embedded in the PCM, but I am not aware of any that do.

There was a Pink Triangle one in the 90s that did, if I recall correctly.

DaCapo?

C.

Salmon Dave posted:

....Of course one of the disadvantages of using a Naim CDP with digital out to a DAC is that you lose the HDCD. This always drove me mad so I sold my dig out Naim CDP.

I have a rather treasured collection of hard-to-find Joni M albums on HDCD....

Dave - not sure I follow - you don't loose the HDCD - its always embedded in the PCM. Its what you do with it. If you had a DAC that responded to the HDCD control messages then indeed you would still have the HCD encoded audio with the digital out of the Naim CDP - or any CDP or streamer for that matter. The Naim DAC however does not do this and am not personally aware of any that do apart from possibly the examples mentioned above. The control messages are so small they are effectively inaudible.

S

Simon-in-Suffolk posted:

[...]

Technically an offboard DAC could equally do this, as all the info needed is embedded in the PCM, but I am not aware of any that do.

 

The Berkeley Alpha DAC is able do do this. Perhaps unsurpringly, as the people behind Pacific Microsonics (HDCD) and Berkeley are pretty much the same.