When a manufacturer wants you to review a
digital output board for the Pi at almost
triple the price they normally go for, you
wonder if they really have something or are
just bolt.
For I will not compromise 
on integrity…..
Every few days people tell me that, since
digital signals are digital, there is no difference
between digital sources.
All kinds of arguments follow, sometimes well
thought out - though wrong - and sometimes
simply ignorant.
Point is that if I only change one digital
source for another, I hear a clear difference
on my three reference setups or, if the difference
is small, primarily on my big setup 1.
And I hear these differences for decades now,
as do a lot of my colleagues.
I you don’t hear any difference, you might
buy better gear and or watch my series on
audio hygiene to improve YOUR stereo.
Or just don’t bother, that’s your choice.
I bring this up here since the subject of
this review is a relatively expensive digital
audio output board for the Raspberry Pi and
the big question of course is: does it sound
better than the clearly lower priced competition.
So buckle up for this one….
Allo sent me a board an a housing and as with
almost all Pi housings, it came as a flat
pack without instructions and made me long
for Ikea constructions.
But on the Allo site there is a clear instruction
video that will help you out.
After assembly you end up with an elegant
looking housing that, especially with the
current non-spring loaded microSD slot, makes
it somewhat difficult to change microSD cards
and the same goes for the network connection.
But then again, that’s mainly a reviewer’s
thing.
‘Normal’ people will insert the microSD
and network cable only once and leave it there.
According to Allo there are 10 low-drop-out
voltage regulators.
These have the advantage of having no switching
noise at the expense of some heath dissipation.
Having 10 of them on board means that they
must have been rather careful to supply clean
power to the different parts and - for instance
- keeping the noise from the Pi out of the
DigiOne board.
Added to that they also claim to use DC/DC
converters that do the same but do have switching
noise and lower dissipation.
There furthermore is extensive filtering,
galvanic isolation and then reclocking, using
the Wolfson WM8805 SPDIF receiver to output
the digital signal.
There is no optical digital output, for Allo
considered that to be a waste of quality and
they are right.
I advise to use TOSlink only when I suspect
that galvanic separation is needed.
The TOSlink connector has low bandwidth and
if no galvanic separation is needed, RCA is
a better choice and BNC the best.
Since Allo has provided galvanic separation,
it would be wasteful to provide TOSlink.
Remember the SOtM sMS-200 Ultra review I did?
No, the Allo DigiOne is not that good but
it has the same charme as the sMS-200, the
basic model.
- It performs clearly better than any digital
output board for the Pi I have tested up till
now, regardless the power supply used.
And I used the DigiOne mounted on a Pi 3B
with the normal cheap wall wart connected
to the microUSB on the Pi.
De highs are surprisingly clean, there is
more tonality in the lows compared to the
competition, and stereo image is also clearly
bigger and more defined.
The sMS-200 with sBooster power supply offers
more detail and sounds more relaxed, but then
we are talking about 750 euros of gear as
where a complete DigiOne setup - Raspberry
Pi, DigiOne, microSD card, power supply and
housing - is under 200 euros.
Compared the the HiFiBerry Digi+ Pro, the
DigiOne has clearly superior highs, better
sibilance control, more openness and a somewhat
deeper and better defined stereo image.
It better have, given the price difference,
you might say.
But I use the HiFiBerry Digi+ Pro the way
I described in the video ‘HiFiBerry Digi+
Part 2’.
The link is in the show notes.
That is about the standard Digi+ Transformer
version but the modification I did on the
Pro is the same.
And I used the AudioPhonics linear power supply
that costs 89 euros making the total cost
of the total HiFiBerry Pro setup the same
as the Allo with the cheap wall wart.
Then I came across an interesting phenomenon….
At the end of the day I wanted to enjoy some
music so I selected the USB input on the Mytek
Brooklyn to listen over the SOtM sMS-200 Ultra
that now is standard in my setup 1.
I left the Pi with DigiOne board connected
to the SPDIF input of the DAC and kept it
under power but not selected.
I started playing one of my favourite albums,
‘Urk’ by The Nits - a Dutch band - and
immediately notice something was seriously
wrong.
The album contains strong sibilance but playing
over the Ultra and the Brooklyn that’s no
problem.
But it was now.
Since I always will change only ‘one’
thing at a time in my reference setups, I
knew it must be the Pi/DigiOne combo.
So I disconnected the SPDIF and took the wall
wart from the socket.
Immediately the sound as I know it was back.
It appeared that the switching mode power
supply was the problem so I replaced that
with the Audiophonics linear power supply
and that solved the problem.
It also generated a question.
If the switching mode power supply has so
much influence on the main setup, how would
the DigiOne sound with the AudioPhonics power
supply?
Well, slightly cleaner on the high end and
more relaxed and certainly worth the 89 euros
the AudioPhonics costs or, if you like, slightly
less for the iFi iPower that is a switching
mode power supply done well.
I now couldn’t resist to try the sBooster
power supply too.
That again gave an improvement but only slightly.
Audible on my setup 1 but not on the other
two setups.
And given the alternatives nowadays, it is
not wise to equip a 20k stereo with a Raspberry
Pi and DigiOne.
Although it is fair to say that three years
ago I would have been very happy with the
DigiOne on a Pi and fed by an sBooster.
In my setup 2 - costing around 3k - it is
a very fine solution when used with an AudioPhonics
or iFi power supply.
And clearly the better choice than the competition.
Whether it is worth the money in my setup
3 - a 1k set - I find hard to say since I
was stupid enough to start with my setup 1
and once you have heard the artefacts of a
device, you’ll hear them everywhere.
My guess is that it will be noticed by some
but not all.
For a simple digital output board for a Pi
the price of 99 US dollars seems steep, rather
steep.
But it’s no simple digital output board.
It is of very high quality compared to the
competition.
Sure, use a microRendu or sMS-200 and an audiofile
power supply and you get even more openness,
more detail, cleaner highs and so on.
But the tested setup with a standard power
supply running the RoPieee image and Roon
came at about 65 percent of the sMS-200 using
an sBooster power supply.
Using the Audiophonics linear power supply
brought it to say 75% of the sMS-200 with
sBooster.
And please don’t ask me what 75% means,
I’m just trying to give you an impression
and that judgement will vary depending on
your auditory system and your stereo.
Let me also put it in another way.
If you have a stereo in the same realm or
higher than my setup 1, the best choice I
have found until now is the sMS-200 Ultra
at 1700 euro’s or more including a proper
power supply.
Below that the standard sMS-200 would be my
choice and then the Raspberry Pi with Allo
DigiOne and AudioPhonics power supply.
Please do understand that I haven’t reviewed
all available products on the market and if
there is a manufacturer that thinks its product
is better, please contact me.
This review started that way and I am glad
Allo did contact me.
Developments in digital music reproduction
go quickly now so if you want to stay informed,
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See the show notes for the links.
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advise.
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I am Hans Beekhuyzen, thank you for watching
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And whatever you do, enjoy the music.
