DDC - Digital USB interfaces - Xmos or Amanero Combo384 based - Raspberry Pi - HifiBerry DAC+ Pro - reviews, comparison, modifications and USB-Audio in general

[hgpsemaj]

 
The RPi can send the data directly to the Soekris via I2S. It has a built in FIFO reclocker and galvanic isolator, this takes care of the jitter issues on the RPi I2S outputs.
This is how I use the RPi with the Soekris, I have got 4 of them,
 
This considerably simplifies the setup and reduces RF noise overall.
 
Your friend might see some benefit here, PM me if there is further interest.

 
Many thanks for your offer.

 

[hgpsemaj]

A ready made one with the new Xmos? I'm not that much into DIY, just some basic soldering... maybe if it's not that complicated I'll try it

 
Both Breeze Audio and Diyinhk claimed that they would release new ready made USB Interface in respect of latest Xmos XU208 & XU216 in the forth coming future.

 

[hgpsemaj]

 
Interesting thread on the Raspberry Pi for high end audio:
 
http://www.dimdim.gr/2014/12/the-rasberry-pi-audio-out-through-i2s/
 

 
This interesting thread came with those following replies:
 
Danielon January 6, 2016 at 08:14 said:
You are wrong. The so-called “Master clock” has nothing to do which chip is master or slave. It is usually just a clock that is uses to derive all other clocks. The master clock is not even part of I2S. There is no need to feed a master clock to the Raspberry Pi. The Raspberry Pi can be slave for BCK, LRCLK. These are the I2S clock signals.
We’re using the Raspberry Pi as a clock slave since years (the HiFiBerry Digi that does this has been released almost 2 years ago). Check out the driver source and you will clearly see that the Raspberry Pi runs in slave mode.

Dimdimon December 31, 2015 at 15:40 said:
Are you sure about that? AFAIK there is no way to feed back to the RPi a master clock, so no way to run it as a slave. What I’m seeing on the DAC+ Pro is an I2S out with MCLK out, obviously generated by the DAC+ itself. This I2S output will have the same limitations as the RPi’s on-board I2S output, since I see no reference to reclocking being done on-board the DAC+. I may be wrong of course.

Daniel on December 31, 2015 at 14:54 said:
The Raspberry Pi can work a a clock slave completely eliminating the clock jitter issue. The easiest way to do this is using an HiFiBerry DAC+ Pro:http://support.hifiberry.com/hc/en-us/articles/205711451-DAC-Pro-connect-external-I2S-DACs

 

[b0bb]

 
Interesting thread on the Raspberry Pi for high end audio:
 
http://www.dimdim.gr/2014/12/the-rasberry-pi-audio-out-through-i2s/
 

 
Straight out of the RPi, the clock is pretty nasty.
 
The fix is not to use the clock as the primary timing source (BCLK), there are 2 methods in common use
 
1)Reclock into a FIFO like Soekris and Ian Jin with the FIFO II reclocker are doing.
2)Slave the RPi to an external BCLK generator like HiFi Berry is doing.
 
Like USB to I2S, the problems with Direct I2S, are quite fixable, I have done both.

 

[hgpsemaj]

Extract from other forum, Soekris R2R DAC:
 

 
 

 

[rb2013]

Straight out of the RPi, the clock is pretty nasty.

The fix is not to use the clock as the primary timing source (BCLK), there are 2 methods in common use

1)Reclock into a FIFO like Soekris and Ian Jin with the FIFO II reclocker are doing.
2)Slave the RPi to an external BCLK generator like HiFi Berry is doing.

Like USB to I2S, the problems with Direct I2S, are quite fixable, I have done both.

Thanks, that makes seense. Interesting new solution from an unexpected source.

I found that blog since DimDim just posted to my XU208 thread.

One question: can the rasp pi solution feed fom a PC or Mac, using say Foobar as the player ( sub in your fav PC/MAC player), or do you have to use these clunky html players?

Cheers!

 

[rb2013]

https://hifiduino.wordpress.com/2014/11/13/raspberry-pi-b-digital-audio/

Great Rasp Pi source, I have been posting there for years, going back to HiFiduino's Musiland 3.0 days. And why I started the Seokris R2R thread.

Cheers!

 

[rb2013]

http://www.head-fi.org/t/803111/xmos-xu208-usb-bridges-the-latest-gen-has-arrived
Both Breeze Audio and Diyinhk claimed that they would release new ready made USB Interface in respect of latest Xmos XU208 & XU216 in the forth coming future.
[/quote]I think you 'forgot' to mention the currently available Singxer F-1 solution. The best USB DDC I have heard by miles ( and I've heard about 15, including introducing the Brreeze Audio DU-U8). This $157 currently available solution is in a class of it's own. Light years ahead of any other DDC I've heard.

You can follow the thread I've started here:

 

[b0bb]

One question: can the rasp pi solution feed fom a PC or Mac, using say Foobar as the player ( sub in your fav PC/MAC player), or do you have to use these clunky html players?

Cheers!

 
RPi based players operate on a different paradigm, the player software runs inside the RPi, this is the equivalent of foobar.
Foobar can be configured as a DLNA control point to talk to a RPi running the right software, in this case the main playback engine in foobar is not used.
 
Most run a version of embedded realtime-linux that is dedicated to music playback only, and is configured for bitperfect playback (ALSA hardware passthru in most cases).
 
The conventional player is reduced  to a user interface shell, so the player can be controlled from PC/MAC or a phone or iPad tablet, and yes you can get a web based player as well.
 
The actual music repo varies with the software used, with Logitech Music Server it is a central server, with Volumio, the RPi mounts the remote disk directly

 

[rb2013]

RPi based players operate on a different paradigm, the player software runs inside the RPi, this is the equivalent of foobar.
Foobar can be configured as a DLNA control point to talk to a RPi running the right software, in this case the main playback engine in foobar is not used.

Most run a version of embedded realtime-linux that is dedicated to music playback only, and is configured for bitperfect playback (ALSA hardware passthru in most cases).

The conventional player is reduced  to a user interface shell, so the player can be controlled from PC/MAC or a phone or iPad tablet, and yes you can get a web based player as well.

The actual music repo varies with the software used, with Logitech Music Server it is a central server, with Volumio, the RPi mounts the remote disk directly

Honestly that's fairly confusing to an experienced user like myself, for a newbie pretty challenging. But my hope is with technological advancement ( we're already on V.3 now), this gets inbedded into a more user friendly device or UI.

I'll keep watching.

Cheers!

PS Do the music files feed into the RPi USB, or the PC, in the senerio you describe. Seems like processing hi res files would tax the RPi resouces while also doing the audio processing. Just like a dedicated pc, with a lot less processing juice - AC and MFLOPS.

 

[b0bb]

Honestly that's fairly confusing to an experienced user like myself, for a newbie pretty challenging. But my hope is with technological advancement ( we're already on V..3 now), this get inbedded into a more user friendly device or UI.

I'll keep watching.

Cheers!

Think of the system as a PC with foobar dedicated to every DAC in the house. The PC listens for commands from a remote controller.
 
You run the remote control software on your PC/MAC, phone or ipad. This takes care of the play lists,  search and browsing, it then sends the commands to the PC to start playback on the playlist.
 
The real achievement is squeezing all of this into a $40 package, the more common use is to connect the RPi and the DAC via USB, I2S directly to the dac is the next step in the evolution. (The RPi becomes part of the DAC providing ethernet as another input option)

 

[rb2013]

Think of the system as a PC with foobar dedicated to every DAC in the house. The PC listens for commands from a remote controller.

You run the remote control software on your PC/MAC, phone or ipad. This takes care of the play lists,  search and browsing, it then sends the commands to the PC to start playback on the playlist.

The real achievement is squeezing all of this into a $40 package, the more common use is to connect the RPi and the DAC via USB, I2S directly to the dac is the next step in the evolution. (The RPi becomes part of the DAC providing ethernet as another input option)

See my P.S.

But OK, now you have a PC, storage devices, RPi, all interacting perfectly together. Pardon the skepticism. Been around digital stuff for far to long, way brittle...then you have more in the chain like i2s converters DAC of course.

Seems like a solution, in search of a problem...very Engineering...

 

[b0bb]

See my P.S.

But OK, now you have a PC, storage devices, RPi, all interacting perfectly together. Pardon the skepticism. Been around digital stuff for far to long, way brittle...then you have more in the chain like i2s converters DAC of course.

Seems like a solution, in search of a problem...very Engineering...

 
Did not see your PS initially.
 
 
A standalone application closer to a conventional PC is Rune Audio which pulls in the audio files without the need for another PC other than the file server itself.
http://www.head-fi.org/t/795895/a-70-bit-perfect-audio-player
 
I use LMS with the RPi and it is a little different but that is a software choice rather than a RPi specific, that probably made the RPi sound more complicated than it was.
 
I2S makes sense only if one is able to connect the RPi directly to the DAC on the DAC motherboard, going thru I2S converters nullifies some of the benefits.
 
The RPi2 and above will play 384kHz tracks without dropouts, RPi2 is a 900MHz 4core ARM with 1Gb of memory
RPi3 is 1.2GHz
 
Some numbers on my RPi2 Picoreplayer on the RPi:
DSD128 as DoP (equivalent to 384kHz PCM): Approx 20% of 1CPU core, 0.20/4 = 5% busy overall (load average: 0.20)
Track is one of the Native DSD tracks justlisten_JL001_JL001+stereo_05_Mahler1_finale_session_BFO_DSD128_2ch128.dff
 
PCM 352kHz : load average: Approx 11% of 1CPU core,  0.11/4 = 2.75% busy overall (load average: 0.11)
Track is from 2L Krambupolka 2L-068 stereo-DXD 01 15

 

[hgpsemaj]

Hello B0bb,
 
What do you think to pair Raspberry PI3 with this? Please advise
 

[the ZERO] DAC TDA1540 R2R Isolated nonoversampling NOS Audio with FIFO reclock

http://www.diyinhk.com/shop/audio-kits/100--the-zero-dac-tda1540-r2r-isolated-nonoversampling-nos-audio-with-fifo-reclock.html

 

[b0bb]

  Hello B0bb,
 
What do you think to pair Raspberry PI3 with this? Please advise
 

[the ZERO] DAC TDA1540 R2R Isolated nonoversampling NOS Audio with FIFO reclock

http://www.diyinhk.com/shop/audio-kits/100--the-zero-dac-tda1540-r2r-isolated-nonoversampling-nos-audio-with-fifo-reclock.html

Physically it should work as DIYinHK is claiming they fixed data incompatability. The old DACs require a silghtly different formatting for the input words.
 
Unlike modern DACs, the digital filter/DSP is a separate piece like the SAA7220. This is missing on this board, somewhere in the chain the required brickwall filter for CD Redbook audio has to be added, at minimum the DSP like the SAA7220 should be added to do the brickwall filter but with oversampling turned off if you are interested in NOS.
 
If you are using this with amps and speakers, the amp should have a very steep low pass filter above 20kHz to avoid damaging the tweeters in the speakers if this used without the DSP.