Wolfson and MPD  working

Hi,

I'm excited to see that someone actually has the wolfson audio card and got it working with MPD! I'm currently using a USB dac and the pops and clicks are driving me nuts.

So far have you noticed any audio glitches? What's your opinion of the p5 head sprung connector? Does it make a solid contact? I was considering the hifiberry, but the soldering kind of turned me off. I wonder if the sound quality will be comparable.

Thank you!

The Hifiberry appears to use the same IC that I've tried on a BeagleBone Black, it is a very high quality part (used in $300 Meridian USB sound cards), but it looks like the hifiberry does not have an on-board oscillator which is needed for good audio quality. I could be wrong. Just going by the photo here about a third down the page. I don't see an oscillator but perhaps it is on the rear of the board.

The Wolfson board is lower cost (and more functionality - including digital out) and it would make sense to go with that one I think. But I don't have experience with it.

From a hardware point of view it won't have effects like skip or anything like the USB ones you've experienced. The interface is very different, and is at a determined rate with no contention from other devices like USB. It is a dedicated audio interface.

@saltrock

Hi,

Answer to your questions:-

So far have you noticed any audio glitches?

No, but I am using the sdcard as the MPD music directory, if you read my post above, I am going to try it with a nsf mount directory form my NAS.  At 192kbps data rate that should really test the PI's USB driven ethernet port.

What's your opinion of the p5 head sprung connector? Does it make a solid contact?

I was a bit worried about the P5 connector,  you have to assemble it CAREFULLY, as ther is a 20pin I/O connector to align at the same time.  Once you have it in place and secured, you can check that it is in good contact by turning the PI upside down and looking at the P5 holes. You should see the tip of the spring connectors in each hole.   I don't know how durable it will be if you put it on and took it off every day though.  Once in place it works well.

I was considering the hifiberry, but the soldering kind of turned me off.   ANS:_ I think you can get the Hifiberry completely soldered at extra cost!

I wonder if the sound quality will be comparable.  ANS:- The DAC is the same 5102, however I think the Wolfson has better power filtering. 9 and of course it does inputs AND it has a a low power loudspeaker driver and stereo microphones on the card!

Too many toys to play with and not enough hours in the day.

cheers

Patrrick

Shabaz, thanks for the reply. I wonder what I'll do with my pifacecad after I get the wolfson card. I wonder why wolfson recommends not using a usb hub when using the card? Power?

Superpat,

Thank you for the reply!

I currently attach my pi to an NFS share also. Sometimes I hear glitches, sometimes I don't. It's funny because i don't necessarily hear more clicks with a 24 bit 96khz file even though it takes more bandwidth to transfer. That's all I listen for lately. I just tried putting an album on the sd card just to hear if maybe the usb wasn't the only factor. I swore I heard a click.

I did read that you can order the hifiberry with connectors pre soldered, BUT you still have to solder the p5 header to the pi itself. I'd much rather solder the rca connectors to the hifiberry than try to solder those micro pin holes that are like 1mm apart from each other on the pi.

I read the hifberry uses a burr brown dac, but I only see that the wolfson uses a wm5102 audio hub codec. What is an audio hub codec?

That 2 watt amp would be cool. I should find a pair of Klipschorn to hear how it will sound!

Do you happen to know if an IR module can be used on the expansion header?

Good question on the hub. I think it must be related to some power thing, but it's just a guess : ( I don't use the RPI or BBB with a keyboard/mouse so I've not needed a hub so far (I just use SSH to access the device via the network).

Hi,

As promised an update on using the Wolfson Audio card,  with the music source as a NFS mounted drive  (from my NAS). using wired ethernet.

Playing my favourite  artist, Miles Davis  2011 release Amandia at 24 / 192kbps  var bit rate up to 5857  kbps  2 chan.  flac.

Firstly   the Nas / MPD  combination has always worked fine with a NFS mount on various boards. inc Beaglebone and Cubieboard, and some old x86 mini pc's.  BUT my  Rapspberry PI has ALWAYS stuttered / brief pauses (using various  USB DAC's  @ 192kbps)

Despite member  shabaz's confidence that it will work with a Wolfson Audio I2s DAC.  I have to report:- 

On 24 /96kbps   The raspberry Pi and Wolfson audio card work well  via the NAS.

but

On 24/ 192 kbps There is a very brief pause every minute or so on the audio when playing file via the NAS.  

I next down loaded  a couple of the 192 kbps tracks onto the Pi's SD card. and  played them  using mpd from the card.

RESULT!   perfect reproduction.  No g;itches or pauses.

There is nothing else using the NAS or the internet at the time  I eas getting the pauses on MPD.  but I never have been able to use the PI, MPD and my NAS although other boards work fine.

UMMV !!!!!

regards

Patrick

If you're using FLAC files at 192kbps 24-bit, this is possibly over 100MB file size per song.

So, you're talking a desired transfer rate of a few Mbps your software is streaming this in real time without buffering adequately.

If you do get pauses it's likely to be a problem elsewhere rather than a fault of the audio board.

You'd need to investigate the audio player software, or network, or you could write some software to temporarily transfer the music file to local storage

before playback.

EDIT: calculated the Mbps figure wrong earlier.

 

I wonder if the sound quality will be comparable.  ANS:- The DAC is the same 5102

Just to be clear, the devices are not the same. The PCM5102 is not the same as WM5102, they are different parts (with different functionality) from two separate manufacturers.

Hi Shabaz

I think you have overlooked the point I made, in that My NAS  feeds 192kbps flac files to several other  cpu / mpd combinations,  (Cubieboard, Beaglebone black, x86 700mkz  thin clients and micro computers),  WITHOUT any glitches.

It is only on the Raspberry PI,  whether with an USB DAC or the Wolfson board that I get  any pausing or glitching at 192Khz.

I know it is a throughput problem, but it not straightforward  It is NOT the bandwidth of the NAS.

I have spent some time on this previously with the Pi and USB dacs trying various buffer set ups for MPD, (there is an entry for this in mpd.con), but it never fixes the pauses.

It appears to me to be either a Raspberry PI silicon problem,   (The ethernet on PI's is  derived from the usb channel), a firmware problem at the lowest level or a driver problem

regards 

Patrick