 The first sound card for the Raspberry Pi I encountered came from the Swiss company HiFiBerry. A lot has happened since and although the company focuses on high performance low price products, their recent introduction is a nudge up. This is the sound card. We audio files to 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 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 the operating system on. This makes the Raspberry Pi function as a streamer or network bridge. After you have selected an operating system, on which later on more, you connect the analog outputs to the line inputs of an amplifier, for instance on 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 play and 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 the white metal case that only fits the DAC plus Raspberry Pi 4B. It measures 110 by 90 by 70mm which is only a few mils 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 outputs of the Raspberry Pi board. On the top side we see two USB-2 sockets, two USB-3 sockets and the internet socket. Out of sight on the opposite side there is the microSD card slot. Like all boards for the Raspberry Pi, the DAC2HD has the 40 pin connector on the underside. But the HiFiBerry has duplicated the pins of the Raspberry Pi on 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 the power supply to if you want to have it enter here and then send to the Raspberry Pi, that might offer a better sound quality. A comprehensive power regulation and filtering is found here within the middle of Texas Instruments DC-DC converter that on the secondary side offers a very stable DC voltage. The DAC chip is the 8x oversampling Burr-Brown PCM 1796 and has the clock crystal very nicely closed by. 35532 op-amps convert the balanced output of the DAC chip to a single ended line level signal. You might wonder why this DAC2HD board costs so much more than for instance their DAC Plus. So let's place them side by side. The power input is in the same position but since the DAC Plus on the right came without a connector, I soldered one on and while doing that reversed it to keep it in the housing. Now let's compare how the incoming 5V DC is handled. The DAC2HD on the left has the DC-DC converter with comprehensive filtering followed up by a voltage regulator, while the DAC Plus only has a single capacitor and a voltage regulator. While the DAC2HD has one single CSC crystal, the DAC Plus has two crystals, I'll get back to that. The DAC chip in the DAC2HD is followed up by three op-amps while the DAC chip on the DAC Plus has to drive the outputs directly. So only based on the component count, the DAC2HD must be more expensive. But does that lead to a better sound quality? I can only confirm that the sound quality of the DAC2HD is clearly higher than that of the DAC Plus. 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 the 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 off to spend more on a better power supply. Already the 59 euro iFi iPower 5 volts makes a clear difference and the SBooster BOTW PMP Eco brings it yet to another nut shop. It then also performs great reproducing sibilants and ranks in the low end of my reference setup too. I mentioned that the DAC Plus has two clock crystals while the DAC2HD 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 Plus can do 384 kHz while the DAC chip on the DAC2HD can only do 192 kHz. Yet I would clearly choose the DAC2HD so be careful when trying to interpret specifications. As I've said before trust your ears young viewer, your ears your 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 the Linux ALSAM 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, Rupee when I want the Pi to function as a Roon endpoint or Rupee XL when I want it to function as a DLNA renderer. You have to use special software to copy this so called image to a microSD card. This is not difficult, just follow the instructions you find on the site you get the software from. You then stick the microSD card in the 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 some settings to actually get it working. The Volumio donation software uses a setup sequence that asks you questions. Rupee does it all automatically and is also donation software. There are also free DLNA server programs and players to be used with Rupee XL. To use it with Roon, you need a paid 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 Raspberry Pi for audio reproduction might even confront the more experienced computer buff with Riddles. Riddles he will absolutely solve after doing some investigations but that is where the computer illiterate will get lost. And there are also equally good ready to use solutions costing about the same of 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 word every penny. But stating that with a Raspberry Pi you can have a quality streamer for €39 is rather far from the truth. The 3.5mm audio output on the Pi sounds horrible. What is nice is the flexibility of the Pi. You can start out with a Pi, a €27 DAC board like the DAC Plus 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 find your favorite, you send the makers some money, like many of you also send me money as a token of appreciation. Which brings me to the end of this video. I love to see you back next Friday at 5pm 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 like 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.