IQaudIO DAC+ headphone amp - no sound

leveller

Has anyone had problems with the headphone amp on the DAC+? I can't seem to get any sound through it. I've got the DAC+ enabled in RuneUI and sound is working fine through the phono cables. I've tried different headphones and also tried different versions of RuneAudio (0.3 and 0. 4). I've opened up alsamixer to check if the headphone amp is muted but I don't have any volume controls at all for the headphone amp appearing in alsamixer.

My hardware is an RPi2 Model B.

Here's some dmesg output (using 0.4 beta of RuneAudio):

dmesg | grep -i iqaudio
[    6.815715] snd-rpi-iqaudio-dac soc:sound: ASoC: CODEC DAI pcm512x-hifi not registered
[    6.815741] snd-rpi-iqaudio-dac soc:sound: snd_soc_register_card() failed: -517
[    6.831536] snd-rpi-iqaudio-dac soc:sound: pcm512x-hifi <-> 3f203000.i2s mapping ok

Not sure what those errors are about but as I said, sound is working perfectly through the DAC+ phono connectors.

config.txt:

cat /boot/config.txt | grep iqaudio
dtoverlay=iqaudio-dacplus

Here's some of the kernel modules I have loaded:

lsmod | grep -i iqaudio
snd_soc_iqaudio_dac     4300  1
snd_soc_core          153224  3 snd_soc_pcm512x,snd_soc_bcm2835_i2s,snd_soc_iqaudio_dac
snd_pcm                88980  4 snd_soc_pcm512x,snd_soc_core,snd_soc_iqaudio_dac,snd_pcm_dmaengine

Interestingly there's a module loaded for the PCM5122 chipset which according to the DAC+ manual "delivers variable output (hardware volume control) analog audio to the Pi-DAC+’s Phono connectors." However there doesn't seem to be a specific module loaded for the headphone amp which is a TPA6133A.

bouncingboffin

I am having the exact same issue too on the same hardware. As the headphone IC should be directly connected to the DAC, I wonder if I have a faulty board. When I get a moment, I'll try the IQAudio board on a Pi3 and see if there it is a GPIO line controlling muting or some weirdness.

rawdevice

Hi,

Have you checked your alsamixer settings? You can use the instructions below for the correct settings. Refer to section 13 on pages 31-32.

http://www.iqaudio.com/downloads/IQaudIO.pdf

You will need to log in to your pi via ssh (login root/password rune) to run alsamixer.

A quick way to check the current settings is to use the RuneAudio web GUI using the IP address of your pi and the port 8080 as in:

http://<your pi IP address>:8080

Select the IQAudiODAC soundcard on the top right-hand corner of the webpage and check the values for Analogue Playback and Analogue Playback Boost. Both should be at 100% as per the documentation from IQAudiO. FYI, below are pictures of my alsamixer settings and the corresponding RuneAudio webpage from my setup:

: alsamixer.jpg (93 KiB) Viewed 2795 times

: alsamixer_web.jpg (202.79 KiB) Viewed 2795 times

My MPD settings for the DAC are below:

: mpd_configuration.jpg (93.86 KiB) Viewed 2794 times

Hope this helps,

RawDevice

bouncingboffin

I found the problem by scoping the output from the PCM5122 to the TPA6133, as I assumed, if there was audio present on the line out then there has to be headphone out. The problem turned out to be purely mechanical, the 3.5mm socket is very cheap, the ground finger was pushed up and wasn't making contact with the headphone jack, A poke with a screwdriver and a blob of hot glue has sorted it. It's a shame the product is let down by a cheap headphone socket

Lodewijks

Thanks for sharing. I also spend hours on thinking "what am I doing wrong". And indeed, it is only a broken socket. Not sure how to repair, as if I shuffle the plug a little it sometimes gives a sound. For the time being I use the RCA from the pi-dac+ without the headphone socket.