Audiophile, High Quality RPi-DAC for Raspberry Pi

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Overview Schematics RPi-DAC-RCA+ Home RPi-DAC-Dual RPi-DAC-SPS RPi-DAC-SPDIF RPi-DAC-FPGA RPi-DAC-IF Order
RPi-DAC_Spot

RPi-DAC - rev.5 available

  • works with updated Raspbian and Volumio
  • 1x PCM1794A - 24bit DAC [1]
  • 4x LME49990 - low noise opamp (soldered)
  • 1x TPA6120A - headphone amp
  • 6x TPS7A4700 - low noise LDOs, separate for each rail
  • 4x Schottky bridge rectifiers, 2A, optional for AC input, or use SPS
  • same size PCB (1:1): double layer, both sided SMD equipped, directly stackable with Raspberry Pi
  • Raspberry Pi mounting holes
  • optional: RPi-DAC SPS - Switched Power Supply new

Blockdiagram

RPi-DAC Blockdiagram

The +3.3V is derived from a +6V LDO.

The connector P5 on RPi with the I2S signals plugs in directly on the RPi-DAC PCB connector

The mounting holes can be used in order to assemble with stands, directly. The RPi can be stacked, on top of the RPi-DAC.

The Crystal OSCillator is not needed for RPi. The DAC needs a SCK signal which is not provided by the Rpi. The BCK signal can be used as SCK (a splitter is available on PCB via Jumper Header).

Rasbian and Volumio

In order to use the RPi DAC on a Raspberry Pi - there are the following constraints:

  • You need a version B, with 512MB RAM. This one has the P5 connector where the I2S are provided.
  • No need to compile or to install a Linux kernel: RPi DAC works with updated Rasbian and Volumio!
    		•

    Rasbian

  • have a Rasbian image installed on SD, do on RPi:
  • apt-get update
  • apt-get upgrade
  • rpi-update
  • ldconfig
  • edit /etc/modules/ and /etc/modprobe.d/raspi-blacklist.conf
  • reboot
  • enjoy listening to sound
    		•

    Volumio

    Volumio is the new Linux system to enjoy network attached audio players, formerly RaspiFy

  • see: Volumio
  • download image: Volumio Beta1Pi
  • place image on SD card
  • start RPi and configure from web browser (open Volumio in browser)
  • enjoy listening to sound

    • PCB - Top

    RPi-DAC PCB Top

    PCB - Bottom

    RPi-DAC PCB Bottom

    Assembling rev.4

    PDF - how to solder LDOs - rev4

    please ignore the PDF error and press OK

    Bill Of Materials (BOM) - rev.4

    parts and order numbers

    RPi-DAC DualMono Complete

    RPi-DAC DualMono Complete

    Design files and docs

    BOM_RPi-DAC_rev6.pdf (61K)

    RPi-DAC_rev_6.pdf (1,003K)

    UltraDAC_RPi_rev7.zip (82K) ExpressPCB file (ZIP)

    RPi-DAC_operate.pdf (85K)

    RPi-DAC-operation_ger.pdf (13,209K) (in German)

    Rpi_P5_I2S.pdf (10K) P5 RPi connector pinout

    Pictures
    RPi I2S P5 header
    RPi-DAC assembled RPi-DAC Top RPi-DAC Bottom RPi-DAC Compare Size RPi-DAC Stacked RPi-DAC Stacked 2 RPi-DAC Standalone RPi-DAC Standalone Back RPi-DAC Standalone 2 RPi-DAC 2
    RPi-DAC rev.1 assembled (top) RPi-DAC rev.1 assembled (bottom)
    RPi-DAC rev.3 with RPi and SPS RPi-DAC rev.3 with RPi and SPS
    RPi-DAC assembled with SPS RPi-DAC assembled with SPS
    RPi-DAC assembled RPi-DAC assembled

    References

    [1] see detailed circuit datasheets of original manufacturers

    [2] http://blog.koalo.de/2013/05/i2s-support-for-raspberry-pi.html

    [3] http://m.review33.com/forum_msg.php?db=1&tstart=0&s=&topic=12121012073605&start=45&sort=&number=65

    [4] http://elinux.org/RPi_Kernel_Compilation

    [5] http://abc002.blogspot.com/2013/05/raspberry-pi-alsa-i2s.html