HiFiBerry DAC+
http://www.hifiberry.com/dacplus

- Dedicated 192kHz/24bit high-quality Burr-Brown DAC for best sound quality
- Hardware volume control. You can control the output volume using “alsamixer” or any application that supports ALSA mixer controls.
- Connects directly to the Raspberry Pi, no additional cables needed
- No soldering. Comes as a pre-fabricated kit. You just plug it onto the Raspberry Pi B+, conform to the Raspberry Pi hardware-attached-on-top (HAT) specification.
- Compatible with Raspberry Pi model B+
- Directly powered from the Raspberry Pi, no additional power supply
- Ultra-low-noise voltage regulator for optimal audio performance
- Available with different output connectors: RCA or 3.5mm phone jack. The phone jack version is slim enough to fit into existing enclosures.
- Integrated EEPROM for automatic configuration (with write-protection).
- Comes with all components required to mount it. We include 4 M2.5x12mm spacers to fix the board onto the Raspberry Pi.
http://www.hifiberry.com/digiplus

- Dedicated S/PDIF interface chip supports up to 192kHz/24bit resolution
- Optical (Toslink) and electrical outputs
- Bit-perfect output, audio data stream will not be modified in any way
- Connects directly to the Raspberry Pi, no additional cables needed
- No soldering. The Digi+ comes as a pre-fabricated kit. You just plug it onto the Raspberry Pi B+. The board conform to the Raspberry Pi hardware-attached-on-top (HAT) specification. That means it perfectly fits your Raspberry Pi B+.
- Directly powered from the Raspberry Pi, no additional power supply
- Optional: high-bandwidth output transformer provides full galvanic isolation of the electrical output (not in the standard version)
- Integrated EEPROM for automatic configuration (with write-protection).
- Comes with all components required to mount it. We include 4 M2.5x12mm spacers to fix the board onto the Raspberry Pi.