An introduction to computer audio
Raspberry Pi & Co
If your smart phone can do things like Internet, video, etc it is because it is a very powerful miniature computer.
Let’s use this platform to build a Music Server.
The most popular is probably the Raspberry Pi.

HATS
A HAT (Hardware Attached on Top) is a card you put on top of a Pi.
It slides onto the 40 pin connector. No soldering needed!.
At boot time the HT is recognized and configured by the Pi.

Add a 24/192 capable Wolfson DAC € 38,95

Add a box € 24,95

There you have your 100,- music server.
Allo BOSS I2S DAC V 1.2 $65

- BOSS 1.2 is a Master DAC compatible only with RPI 2 and 3
- Compatible with OSMC / Max2Play / RuneAudio / Volumio / Moode / PiCorePlayer / PiMusicBox / OpenELEC and others + Roon Ready
- Dedicated 384 kHz/32bit high-quality DAC PCM5122 for best sound quality
- Audio output connectors: 2 x RCA (Left & Right ) & Allo Volt Amp header
- HAT size
- Sampling Frequency ranges from 8 kHz to 384 kHz
- Ultra-low-noise voltage regulators & LPF for optimal audio performance
- Integrated EEPROM for automatic configuration (with write-protection)
- Automatically switching frequencies according to the input I2S signals
What kind of performance can we expect for $65?
Amir measured this DAC.

Not into DIY? At 169,- they put it in a box for you.
BOSS 1.2 PLAYER, NETWORK MUSIC PLAYER $169.00

- A 1.2GHz 64-bit quad-core ARMv8 CPU
- 802.11n Wireless LAN
- Bluetooth 4.1
- Bluetooth Low Energy (BLE)
- 1GB RAM
- 4 USB ports
- Ethernet 10/100
DAC
SD Card
- 8GB SD pre-flashed or add-on eMMC 16GB
- DietPi, Max2Play license or latest Volumio image will be provided
Casing
- Black Aluminum or Clear/Black Acrylic Case
- Case Dimensions: 105mm x 93mm
Added 2018
SPDIF card with transformer coupled output providing full galvanic isolation. €34.90
HIFIBERRY DAC+ PRO XLR €49.90

Added 2018
Allo USBBridge $189

Sparky computer with high quality USB audio out.
Added 2017

One DAP (Digital Audio Player) for all your music: MP3, FLAC, WAV, AAC, ALAC, DSD and much more. Plus, you’ll get UPNP\DLNA, Airplay, Spotify and Web-Radios all in one place.
Open Source media player.
Debian/MPD based with DLNA and Airplay.
Platforms:
Raspberry Pi
BeagleBone Black
SolidRun CuBox
UDOO
Added 2016
References
Raspberry Pi 3 as USB Audio Streamer (with recommended CRAAP config & TIDAL/MQA arrives) - Archimago's Musings