Despite the problems I had setting the Audiophonics DigiPi in operation, which are caused by missing product documentation and poor support from Audiophonics (see http://volumio.org/forum/audiophonics-digipi-raspberry-i2s-digital-interface-t2255.html), I have to say that the DigiPi itself offers a very good value for the money!
You get an optical and a transformer decoupled electrical S/PDIF output capable of at least 24bit/192kHz. Coudn’t try higher sampling rates because of my DAC didn’t support them. The board is based on the Wolfson WM8804,
And as a very nice bonus it comes with an OS-Opto IR receiver! This is easily set up working with volumio following sid_d’s guide http://volumio.org/forum/using-remote-with-volumio-t1923.html. Many thanks for that.
If you’re interested in the DigiPi, you’ve to solder P5 as well as P1 (because of the I2C) and configure volumio to hifiberry digi. The output of the IR receiver is available on GPIO18 (pin 12 on P1). Consider that when following sid_d’s instructions.
Room for improvement may be to replace the oscillator by a dedicated low jitter type…
BR
Michael
Merci Michael.
Je viens de commander le Digipi.
As-tu fait des comparaison avec autres sources digitales ?
Roberto
Envoyé de mon Nexus 4 en utilisant Tapatalk
Roberto,
I don’t speeak French, but from google translations I took that you’re about ordering the DigiPi and asking for comparision with other digital sources.
I’m using a PS Audio PWD MKII for D/A conversion. The only comparision I made so far was between a CD played by my Meridian 506 used as a transport only and the same CD ripped to my NAS in FLAC format and played by the Raspi & DigiPi connected by Ethernet.
Both connected via electrical S/PDIF and the same digital cable (Inakustik Reference on/off).
I feel that the sound from the Pi is a tiny bit more smooth, relaxed and of darker tonal balance. But this is more a feeling than a secured perception. And I would bet on it to hear these differences in a blind test. But results may differ with the DAC you use. I used the PS Audio in the NativeX mode, where most of the jitter on the input signal is removed by using FIFOs and reclocking (Digital Lense).
Anyway, I think it is a good idea to have a galvanic isolation (transformer) to prevent any potential balancing between the Pi and the rest of your system.
BR
Michael
Hi Michael,
Thanks for the reply, maybe I’ve drunk too many champagne here in France, so I read in English and replied in French. 
My actual system is composed with a eeepc (linux et mpd) connected via USB to a modified dac Beresford 7520.
I’m so curious to known if I’ll capable to listen some difference with the direct Spdif output.
I’m less curious about the possibility to play 24bit files, because I don’t have many hd tracks.
Roberto
I’ve soldered the DigiPi card, activate the I2S driver on Volumio and…
It’s works!
I tried both S/Pdif and optical outputs with good results.
I’ll write more details about audio quality after some listening test.
Thanks Michael for the right tip and all Volumio staff for made it easy.
Roberto
In my opinion audible differences of digital sources and cables are caused by jitter, high frequency noise from cheap switching mode powersupplies and ground potential differences between deveices balancing through singnal ground.
High frequency noise and ground potential balancing are adressed by a transformer whose limited bandwith also limits hf noise. Of course a optical connection also cuts ground loops, but on the other hand it most ofter has high jitter, depending on the quality of the optical cable.
So it’s always a good idea to have a transformer on the S/PDIF line. Especially on budget deveices with simple power supplies like a RasPi.
Jitter maybe adressed by any jitter reduction means in the DAC (recklocking or what ever).
I’m interested if you’re able to spot any differences between your digital sources!
Michael,
I’m interested in doing some comparative tests. I find for example the transport used can have a big influence.
What NAS drive are you using ?
What do you use as the server, NAS or Volumio ?
I’m interested in looking at the digi but don’t have one to test yet.
Did you try using USB from Pi to your PWD DAC ? If so what were the results like ?
Have you had any success with i2s from pi gpio to PWD ?
I tried this with Project DAC but with no success.
Kevin
Sorry Michael,
Forgot about this post hangs-when-playing-wav-over-upnp-t2301.html
Some are repeated questions, some new.
Hope to look into some stuff next week,
Kevin
Volumio gets it’s files from a Synology DS213j. In my opinion the source of the files shouldn’t make any audible difference.
But I my fail here…
Didn’t try connecting the PS Audio PWD II via USB, because the performance of a RasPi B Rev2 is to low for having interrupt free playback via USB at least with higher bit rates. As I started with volumio I tried a USB soundcard (Sound Blaster) and had exactly that problem. I don’t expect it working with the PS Audio.
I2S: I ordered an Aune I2S - HDMI module from Audiophonics but it turned out to be a receiver module. I’ve to get one from Audio GD to proceed here.
What interface (RJ45, BNC, HDMI) and which DAC is the project using?
BR
Michael
The project has i2s on RJ45 type connector.
I had success with usb direct from synology NAS (select usb speakers in audio station) with both ps audio perfect wave and direct stream. I don’t have a comparison for sound quality though at the moment (e.g. Coax, optical or I2S with pi).
Will try i2s next and maybe purchase a digipi. unfortunately my time is limited as i don’t own the DACS. 