I thought S/PDIF was of no interest at all. I was wrong.
As I’ve said many times: it’s a wonderful time to be an Audiophile. The Raspberry PI has brought back lot of the fun we were missing with digital players, and I still remember that people used to laugh when back in the days I was writing that the PI could be a serious Audophile Media Player.
Luckily, time is a gentleman and it’s now widely accepted that thanks to this little computer we can build a very good Audiophile Music Streamer at a fraction of the cost of comparable commercial solutions. There is no doubt that the best way to maximize its potential is hooking it to a good I2S DAC. And I must admit I considered this the most sensible way to use the PI: thanks to I2S short path of communication, the signal would go straight from the Raspberry PI processor to the DAC, which is on paper the best way to do it (if we don’t mention the jitter problem… but that’s for another day).
So, of course I was totally uninterested of another kind of I2S HATS (an hat is a little board that you snap on top of the Raspberry PI, and I2S DAC are part of this family): the transport HATS. Basically those HATs instead of producing an Analog signal (which you can use directly to feed your amplifier) do produce a S/PDIF digital signal, that is suitable for any S/PDIF external DAC.
The main reason was that many external (and expensive) DACs would also have a USB input: so why bother using S/PDIF? Considering also the fact that the digital signal goes trough multiple interfaces before being received by the external DAC?
But then came Allo DigiOne, and I needed to rethink my position on SPDIF transports.
What is the Allo DigiOne
The Allo DigiOne is a Raspberry PI HAT (see above) that directly connects on top of a Raspberry PI. The DigiOne takes the audio signal straight out from the I2S connection available on the Raspberry PI, and outputs an S/PDIF digital signal that can be fed into any S/PDIF external DAC.
There are many S/PDIF Hats out there that achieve the very same result than the DigiOne, but the DigiOne has several aces up its sleeve that make it probably the best S/PDIF transport HAT there is.
I’ve already written an extended review here, and here’s the sum of what makes the DigiOne so special:
- DigiOne has 2 high quality onboard Clocks, therefore its immune by the Raspberry PI I2S jitter problems.
- It applies a meticoulous filtering process on the DC coming from the Raspberry PI
- It isolates each stage of the signal path with a galvanic isolator separating the Raspberry PI from the clocks and the clocks from the S/PDIF transmitter
Allo themselves quote that the DigiOne, in fact, is “a master codec with digital/electrical/ground isolation from RPI AND wm8805 and a reclocker”.
All the above means that the Digione truly is the most advanced and better sounding S/PDIF transport HAT currently available. As you can read in my review: this is the only S/PDIF transport that gave me comparable results than USB connection (with iFi iPurifier2), and that in itself is quite an achievement.
This is an extract of my full review:
I tried it on 3 “good enough” DACs, which I usually use connected via USB, in order to compare the outcome of the total chain.
I was impressed: never thought S/PDIF could sound that good. My previous experiences were with other shields and there is a very evident difference. Especially for the things I do care about: detail, soundstage and musicality.
Basically, for me at least, the DigiOne has become the only S/PDIF source that I would have in my system. I find the same level of enjoyment that I do have with the Mini86 and ipurifier (on the same DAC, but connected with its XMOS based USB receiver). I won’t be making any further comparison because it will be like comparing apple and oranges (the implementation of the USB Receiver and S/PDIF receiver of the same DAC can be of different quality level).
So, sonically speaking, well done Allo: this is the only S/PDIF I managed to actually like.
Now, what I don’t like about this. I would have preferred to have a way to feed the DigiOne and the Pi separately. Allo claims there is no need (and they are probably right, considering the DC regulators and galvanic isolation) but I think this is anyway a Nice to have feature.
So my conclusion is: the DigiOne is expensive when compared to similar solution, but it’s definitely worth every penny of it. What we have here is something that was not designed to sound good, but to sound as best as possible (on Raspberry PI), and this is not yet another case of over-engineering: they made clear design choices which my listening impressions confirm to be correct.
The DigiOne Player, a complete system based on Allo DigiOne and Volumio
If you’re scared that all the above means also that it’s very complicated to enjoy the DigiOne, well, keep on reading. I am writing this article because I’ve been asked many many times from people who were curious to try Volumio, but did not know where to start. Therefore there’s my suggestion: if you want a no-fuss, great sounding S/PDIF Audiophile Music Player / Streamer, this is your best chance to get the right one.
Basically, this can be seen as the quickest way to enter into the revolution of Raspberry PI based audio streamers, and from the main door.
The DigiOne Player contains everything you need:
- Allo DigiOne S/PDIF transport Shield
- Raspberry PI 3
- Allo Acrylic Case
- 8GB Micro SD Card with Volumio preinstalled
- 5v Power Supply
The Allo DigiOne Player can be purchased from our Shop, and every purchase will contribute to the sustainability of the Volumio Project.
For those of you who already have the Allo DigiOne Player, let us know how you like it via comments below, or if you have any question regarding this complete player, just ask!