NAS Super-Low Noise Linear Power Supply

[WAD62]

Will....Please, What are the settings for the PCM conversion on LMS to Transcode at the Pi end? I would like to switch this to the Pi end if it is currently
Transcoding at the NAS...(i'm not near the equipment at the moment!)

The default setting for FLAC on LMS is 'Native' (so will send the FLAC as is), it's in the advanced settings/file types/ section...

[WAD62]

A few minor errors in understanding here.

Whilst the data being transmitted is in 'File' format, eg the compressed FLAC file, or the WAV file etc. we are still in the realms of IT, I.E. a reliable File Transfer, so there's all of the standard FTP protocols in place, so the file received by the player is bit for bit the same as the file sent.

Data between the NAS and the Pi isn't in any form other than TCP/IP packets. This is the common internet transport protocol responsible for the webpage in front of you and millions of other reliable information transfers done every second. As you say, this ensures that the data on the NAS arrives at the Pi exactly the same. FTP is a Transfer protocol, not a Transport protocol.

Ultimately the 'File' will need to be converted to a data stream that can be consumed by a DAC, in this case PCM (pulse code modulation, DSD is a newer format), to my mind this is where we start moving out of the IT world and into the analogue world, where interference can occur, and bits are no longer bits etc. The process of converting a 'File' to a PCM stream is transcoding.

The process of converting one encoded data set to another is transcoding. PCM will be derived from the file by the codec built into the Pi and fed into the DAC. This is demodulation. Files are simply containers for various types of data - A/V file containers can contain data in several diffeerent types which is decided by the codec used at encoding time. This is important to know because when transcoding, the final file type will depend upon the new data set. For example, if you convert a FLAC @ 24/192 to 16/44.1, you can either choose to make the new file a FLAC or a WAV. File type is much less important that then actual encoding used within the file container. Video files are MUCH more complicated again

With LMS (logitech media server) running on my NAS, I can choose whether to transcode to PCM at the Server running on the NAS, or at the player/Pi end, I choose to transcode at the Pi end, firstly for network efficiency (I'm only transmitting a small FLAC file not a 2 * 1411 Khz PCM stream), and secondly I want to decouple my player from the NAS, all it does is send the unpolluted FLAC file.

This is essentially correct, the file could be transcoded at the NAS end into a WAV file (which is a file container for PCM) and sent to the Pi over the network for demodulation, or as you have it set up which is indeed more efficient.


It's an interesting thread, but it should be pointed out that improving power supplies to a NAS can only improve the sound by reducing mains noise that affects the analogue components of an audio system. The NAS operates in the digital domain which is agnostic to noise of this sort unless it's so bad that the system will simply just not work anymore. There is no gradual downgrade of a digital network signal - it works right up until the point at which error correction cannot cope and then it stops functioning. It should be remembered that the inside of your PC (or any digital device) is rife with RF noise and it doesn't stop you from logging on the AoS. Error correction within TCP/IP works all the time, it's effects are not felt in the time domain because TCP/IP is a buffered protocol. If anyone tells you that they are getting jitter from their NAS, you are safe to laugh at them. Jitter only occurs in streaming protocols like S/PDIF which are clock locked.

Cheers for the clarification...so that's that theory blown

[Marco]

Hi Marco, I'll try...

Whilst the data being transmitted is in 'File' format, eg the compressed FLAC file, or the WAV file etc. we are still in the realms of IT, I.E. a reliable File Transfer(TCP/IP), so there's all of the standard FTP protocols in place, so the file received by the player is bit for bit the same as the file sent.

Ultimately the 'File' will need to be converted to a data stream that can be consumed by a DAC, in this case PCM (pulse code modulation, DSD is a newer format), to my mind this is where we start moving out of the IT world and into the analogue world, where interference can occur, and bits are no longer bits etc. The process of converting a 'File' to a PCM stream is transcoding.

With LMS (logitech media server) running on my NAS, I can choose whether to transcode to PCM at the Server running on the NAS, or at the player/Pi end, I choose to transcode at the Pi end, firstly for network efficiency (I'm only transmitting a small FLAC file not a 2 * 1411 Khz PCM stream), and secondly I want to decouple my player from the NAS, all it does is send the unpolluted FLAC file.

In the earlier days of Squeezebox, when the players were a much lower spec than a Pi, some people preferred to Transcode to PCM at the server in order to take the load off the puny player (the CPU on the early SBs is a fraction of the Pi's power)...and felt they gained an improvement, hence this option exists in LMS.

Perfectly explained, Will. I get where you're coming from now (mostly)!

EDIT: I've had a quick look at the moode installation instructions, and it would suggest that it's a stand alone player, that can refer to the NAS, so I'm even more confused!!!

Don't know what you mean by the bit in bold, sorry... In terms of the wider issue, doesn't what Paul Hynes outlined earlier help explain where the sonic benefits are coming from?

Marco.

[WAD62]

Don't know what you mean by the bit in bold, sorry... In terms of the wider issue, doesn't what Paul Hynes outlined earlier help explain where the sonic benefits are coming from?

Marco.

In that the moode player is directly referencing the NAS files, rather than it having a server portion, i.e. it's stand alone

I think smegger's post hes somewhat undermined the PCM theory...in that it's still transmitted as a .WAV file

Is your NAS/psu near your HiFi/Pi?

[Marco]

Hi Paul,

I am not sure there is anything that you could do to help with getting things done up here, but I am all ears if you have any ideas.

I meant any help with promoting and/or assisting in any way, through AoS, in the future development and success of Paul Hynes Audio Ltd. You know I really rate your products (and you), so IMO the good guys in the industry always deserve to be supported as much as possible

Not really extravagant as I have been providing SR7 and SR7MR (Multirail) power supplies for powering audio and video servers for years. They are used for both the server and the peripheral digital signal storage and processing items with considerable improvement in sound and video quality. The improvements are very similar to those you found with the SL1200 and Raspberry Pi power supplies.

Interesting... I didn't know you produced PSUs for servers, video or otherwise, and don't doubt that they improve performance considerably.

Essentially they remove a major cause of “digititis” and provide a robust musically engaging and dynamic three-dimensional presentation to music program.

A removal of "digititis": that's *exactly* what the PSU Duncan built me did, along with the rest of what you describe - and that's what I meant by the RPi now reproducing music with greater 'ease', and sounding more 'analogue' for it, for want of a better description.

I sense there will be some exceptional culinary work later this year at Marco Towers. Enjoy the moment.

Yup, we can't wait to have our first dinner party, to 'Christen' it! Shame you're so far away...

Marco.

[Marco]

In that the moode player is directly referencing the NAS files, rather than it having a server portion, i.e. it's stand alone

I think smegger's post hes somewhat undermined the PCM theory...in that it's still transmitted as a .WAV file

Is your NAS/psu near your HiFi/Pi?

No, it's at the other end of the room (although it isn't a very big room), hence wirelessly streaming the music, to save the use of a longish (ugly) ethernet cable, going from the router to the Pi.

The Pi itself is right next to the back of my amp, separated by a pair of (very short) 0.3m interconnects.

Marco.

[WAD62]

No, it's at the other end of the room (although it isn't a very big room), hence wirelessly streaming the music, to save the use of a longish (ugly) ethernet cable, going from the router to the Pi.

Marco.

Could it be simply mains/rf pollution then? Now we're in your area...

Mine's at the far end of the house on a different floor...

[Marco]

Could it be simply mains/rf pollution then? Now we're in your area...

Possibly, but I still feel that there's something more fundamental going on, out with of that.

Marco.

[WESTLOWER]

my head hurts!

Possibly, but I still feel that there's something more fundamental going on, out with of that.

Marco.

[Marco]

Lol - worry not and just try it!

Marco.