Pi - Audio Injector



Fancyed playing with one of these audio injectors.

IMG_0559.JPG IMG_0560.JPG IMG_0561.JPG

You can put the audio injector into an already existing audio setup by splicing it into a sound path. It is simple - plug into the audio injector and plug out again. The original audio can be put straight through. If a straight through isn't what you want, then use the ALSA mixer to turn off the bypass.

The Audio Injector sound card is designed to keep the same PCB profile of the Raspberry Pi, with the PCB edges and GPIO header in exactly the same place. This means that your current add ons and hats will still plug into the Raspberry Pi keeping the same profile, just a bit taller!

Headphones: 50 mW max power into 16 ohm and 30 mW max power into 32 Ohm headphones (check the updates to see more)

Driver : ALSA

Latency: As low as 0.54 ms in or out (that is 540 microseconds !)

Linux : Already integrated into the Raspberry Pi kernel. If you have an older version of the kernel, simply run "rpi-update" if you need to. Edit /boot/config.txt and set dtoverlay=audioinjector-soundcard

DAC and ADC : 96 kHz, 32 bit audio.

Analog Voltage : 3.3 V rail to rail. Separate linear supply to reduce noise.

GPIO : Standard 40 Pin header, broken out above the add on card to accept more add on cards and hats.

It's dac chip is also a wolfson.


Finally got the card running with moodeaudio :D

It was very easy to setup.

Instructions to follow..


The first thing I did was to flash a new raspbian lite img to micro sd card, then made a new file called ssh in the boot sector.
then I installed moodeaudio using these commands:

cd /home/pi
sudo wget -q http://moodeaudio.org/downloads/mos/mosbuild.sh -O /home/pi/mosbuild.sh
sudo chmod +x /home/pi/mosbuild.sh

then start the build

sudo ./mosbuild.sh

you can now build the img directly on the sd card, this can take about an hour and a half to complete.

you can check the progress of the build with the ssh command moslog.

once moodeaudio is installed you need to edit the /boot/config file

use this command to edit the boot config file

sudo nano /boot/config.txt

this is a copy of mine


dont forget to save the file by pressing Ctrl + x and hit y and then enter.

next you will need to entre these commands, to finish setting up the audio injector.

alsactl --file /usr/share/doc/audioInjector/asound.state.MIC.thru.test restore

alsactl --file /usr/share/doc/audioInjector/asound.state.RCA.thru.test restore

next load alsamixer, so you can turn up the volume. the arrow keys, m & space bar will help you, the press esc and store the alsamixer settings with this code

sudo alsactl store

I then renamed the pi to audioinjector, to do this
sudo nano /etc/hostname
change moode to what you want to call it.
next edit the hosts file
sudo nano /etc/hosts
and use the same name from before.

you need to change the bottom, save with ctrl +x then y and enter.

spotify plug in was next.

sudo apt-get -y install curl apt-transport-https
sudo curl -sSL https://dtcooper.github.io/raspotify/key.asc | sudo apt-key add -v -
sudo echo 'deb https://dtcooper.github.io/raspotify jessie main' | sudo tee /etc/apt/sources.list.d/raspotify.list
sudo apt-get update
sudo apt-get -y install raspotify

you can edit the spotify config file with this command

sudo nano /etc/default/raspotify
and change the bitrate to 320 and change the name.

sudo nano /lib/systemd/system/raspotify.service

only change these values

Environment="DEVICE_NAME=audioinjector (%H)"

save with ctrl + x hit y and enter.

the reboot
sudo reboot

now load the web interface for moode eg moode.local or whatever name you picked, click the little m in the top right hand corner of the web page. pick configure and set the time zone and keyboard layout hitting set each time you make a change.

next switch off
Integrated WiFi adapter
Integrated BT adapter
HDMI port

back to the little green m in the top right hand corner of the screen, and pick audio, look for the mpd settings.
set the volume control to disabled.
SoX resampling 24 bit / 96 Khz
SoX quality very high
SoX multithreading yes
Gapless mp3 playback yes
DSD over PCM (DoP) no
Volume normalization no
ReplayGain off

scroll down and switch on airplay, hit set.

and hit apply top left of the screen.

then all I had to do was let it scan my nas.