The first ‘sound card’ for Raspberry Pi I
encountered came from the Swiss company HifiBerry. A lot has happened since and although the company
focuses on high performance low priced products, their recent introduction is a notch up. This is the sound card, we audiophiles use the
term digital to analog converter, abbreviated to DAC. On its own it doesn’t do anything,
you do need to mount it on a Raspberry Pi small board computer and then it looks like this.
If you want it to be more robust, you can build it into a housing like this one from HifiBerry that
holds both the sound card and the Raspberry Pi. To get it working, you also need a matching power
supply and a microSD card that you need to put an operating system on. This makes the RaspberryPi
function as streamer or network bridge. After you have selected an operation system -
on which later on more - you connect the analog outputs to line inputs on the amplifier, for
instance Aux or CD. The network connector in the Pi is to be connected to your router
unless you want to use wireless LAN. But then you want to use an acrylic housing
rather than a metal one. Over the network connection the Pi gets the music from a shared
volume on your computer or from a music player program suited for sending music to a network
bridge, depending on what operating system you have copied on the microSD card. In most cases you
control the player from a tablet or smartphone. Of course you can build your own housing for the
Pi plus DAC combination or use another type by HifiBerry, but I show you here their white metal
case that only fits the DAC plus Raspberry Pi 4b. It measures 110 by 90 by 70 mm, which is
only a few mill more than the naked setup. On one side we see the USB C
power input, two HDMI outputs, the Pi’s own low quality analog audio output
and the high quality analog audio outputs on the HifiBerry board. On the top side we
see two USB 2 sockets, two USB 3 sockets and the ethernet socket. Out of sight, on the
opposite side there is the microSD card-slot. Like all boards for the Raspberry Pi, the DAC2
HD has the 40 pin connector on the underside. But HifiBerry has duplicated the pins of
the Raspberry Pi on the top of the board so you can stack a second board on it, like
the HifiBerry DSP board. Which, by the way, I have no plans to review. A second
connector is for use with the DSP board too. This third connector provides
analog out and power for custom setup. Then there is a connector that can be used to
connect a power supply to if you want to have it enter here and then sent to the Raspberry
Pi. That might offer better sound quality. A comprehensive power regulation and filtering is
found here with in the middle a Texas Instruments DC-DC converter that on the secondary side offers
a very stable DC voltage. The DAC chip is the 8 times oversampling BurrBrown PCM1796 and it
has the clock crystal very nicely close by. Three 5532 op amps convert the balanced output of
the DAC chip to a single ended line level signal. You might wonder why this DAC2 HD board costs so
much more than, for instance, their DAC+. So let’s place them side by side. The power input is in the
same position but since the DAC+ on the right came without the connector I soldered one on and while
doing that, reversed it to keep it in the housing. Now, let’s compare how the
incoming 5 volts DC is handled. The DAC2 HD, on the left, has the DC-DC converter
with comprehensive filtering , followed up by a voltage regulator while the DAC+ only has
a single capacitor and a voltage regulator. While the DAC2 HD has one single CEC crystal,
the DAC+ has two crystals. I’ll get back to that The DAC chip in the DAC2 HD is followed up by
the three op-amps while the DAC chip on the DAC+ has to drive the outputs directly.
So only based on the component count the DAC2 HD must be more expensive. But
does that lead to a better sound quality? I can only confirm that the sound quality of the
DAC2 HD is clearly higher than that of the DAC+. This is already rather audible in my setup 3 but
becomes even more obvious in my setup 2. It offers clearly higher resolution, especially in the mids
and highs. The lows are also good but especially the mids and highs are clearly better. That is
already the case with the regular Raspberry Pi power supply but it really pays to spend more on a
better power supply. Already the € 59 iFi iPower 5 volts makes a clear difference and the sBooster
BOTW P&P ECO brings it yet another notch up. It then also performs great reproducing sibilance
and ranks in the low end of my reference setup 2. I mentioned that the DAC+ has two clock crystals
while the DAC2 HD has only one. But that must be simply of better quality given the sound quality.
Also funny is that the DAC chip on the DAC+ can do 384 kHz while the DAC chip on the DAC2 HD can do
‘only’ 192 kHz. Yet I would clearly choose the DAC2 HD. So be careful when trying to interpret
specifications. As I have said before, trust your ears, young viewer, your ears you trust. Some
last remarks. Depending on the software - or operating system - you can set the volume from
the control software on your smartphone or tablet since it uses Linux ALSA mixer and almost all
music player software for the Pi is Linux based. I use Volumio when I want the Pi to function as
a network player, Ropieee when I want the Pi to function as Roon endpoint or Ropieee XL when I
want it to function as a DLNA renderer. You have to use special software to copy a so called image
to a microSD card. This is not difficult, just follow the instructions you find on the site you
got the software from. You then stick the microSD card in the card slot on the Pi and connect
it to the audio equipment and power supply. Depending on the software chosen you then might
have to do settings to actually get it working. The Volumio donation software uses a setup
sequence that asks you questions, Ropieee does it all automatically and is also donation
software. There are also free DNLA server programs and players to be used with Ropieee XL. To use
it with Roon you need a payed Roon subscription. If you have no affinity with computers you
may prefer to stay away from Pi projects unless you have the proverbial handy cousin.
Setting up a Raspberry Pi for audio reproduction might even confront the more experienced computer
buff with riddles. Riddles he will absolutely solve after doing investigations. But that is
where the computer illiterate will get lost. And there are equally good ready-to-use solutions
costing about the same or only slightly more. A simple setup with metal housing and Pi
power supply will set you back about € 175. With the iFi iPower you will have to shell out €
225 while the same setup with an sBooster power supply will add up to € 475. And yes, I find
it worth every penny. But stating that with a Raspberry Pi you can have a quality streamer for €
39 is rather far from the truth. The 3.5 mm audio output on the Pi sounds horrible. What is nice
is the flexibility the Pi offers. You can start out with a Pi, a € 27 DAC board like the DAC+
and a € 10 power supply and upgrade over time. You can also try out all kinds of software
since most of them are donation ware. So when you have found your favourite, you send the maker
some money, like many of you also send my money as toke of appreciation. Which brings me to the end
of this video. I love to see you back next Friday at 5 PM central European time, in a new video.
If you don’t want to miss that, subscribe to this channel or follow me on the social media so
you will be informed when new videos are out. If you liked this video, give it a thumbs up. Many
thanks to all of you that grant me donations, it makes it easier to invest in gear to make even
higher quality reviews and background videos. If you have not supported my work already, the links
are in the comments below this video on Youtube. It is much appreciated. I am Hans Beekhuyzen,
thank you for watching and see you in the next show or on theHBproject.com.
And whatever you do, enjoy the music.
