IQAudIO Pi-AMP+ stuck in MUTE mode HAT on top of DACPRO board

From the PDF … I tried all the IQAudIO options and all stay muted…headphone on the DACPRO board is OK…Normally set to the Pi-DAC (+/Pro/Zero) option.

@spockfish If you need a feedback let me know or the PDF of IQAudIO stuff as their site is down now.

  1. The Pi-AMP+

The Pi-AMP+ is an add-on accessory for the Pi-DAC+ and Raspberry Pi.

The Pi-AMP+ takes the variable output analog audio from the Pi-DAC+ and through the onboard

Texas Instruments TPA3118D2 Class D amplifier delivers audio to the Pi-AMP+’s speaker terminals
delivering up to 2x35w@19v input.

The Pi-AMP+ requires a 12–19volt power source to operate. Power should be applied via the Pi-AMP
+’s standard barrel connector or the two pin JST socket provided.

The Pi-AMP+, when powered, has been designed to provide power to the Raspberry Pi / Pi-DAC+
and Pi-AMP+ combination safely. You can continue to use your Pi devices without risk of damage. As
with the Pi-DAC+, we’ve focused on the components selected and the attention to audio performance
during PCB layout when developing the Pi-AMP+.

The Pi-AMP+ is by default muted at power on (mute LED lit). Mute state / LED is under software
control (Raspberry Pi GPIO22) but mute may be overridden by shorting the Pi-AMP+’s P9 pins with a
suitable jumper – note the mute LED will remain lit if P9 is shorted.

shorting the jumper works but its a horrid thump /pop in both speakers when powering on/off

@Gordon_Garrity Gordon I am a little perplexed as GPIO22 doesn’t seem to be on the header connection of the Pi-AMP+ board unless it routed through on another point header. Maybe this is the GPIO Mode 3 out which looks like GPIO3…all these references rather confusing

some more info here…both my DigiAMP+ hats work fine with mute/unmute for the record just never used this Pi-AMP+ hat until now.

  1. Controlling the Pi-AMP+ / Pi-DigiAMP+’s Mute / Un-mute

MUTE state is toggled by GPIO22 on the Raspberry Pi. The latest IQaudIO device tree supports the

unmute of the AMP through additional parameters (from Raspbian 4.4.14+ onwards) …


“one-shot” unmute when kernel module loads.


Unmute amp when ALSA device opened by a client. Mute, with 5 second delay

when ALSA device closed. (Re-opening the device within the 5 second close

window, will cancel mute.)

If you do not want to control Mute state through device tree then you can also script your own

solution. The information below may be useful.

The amp will startup MUTED

to unmute the amp.

pi@raspberrypi ~ $ sudo sh -c “echo 22 > /sys/class/gpio/export”

pi@raspberrypi ~ $ sudo sh -c “echo out >/sys/class/gpio/gpio22/direction”

pi@raspberrypi ~ $ sudo sh -c “echo 1 >/sys/class/gpio/gpio22/value”

to mute the amp once more…

pi@raspberrypi ~ $ sudo sh -c “echo 0 >/sys/class/gpio/gpio22/value”

If you already use WiringPi:

If using WiringPi - to unmute the amp

gpio mode 3 out

gpio write 3 1

to mute once more

gpio write 3 0

For the Pi-AMP+ MUTE may also be disabled at startup by using a jumper across the P9 pins. You

may experience a loud crack / pop through attached speakers on power up if this is done. No such

jumper pin is available on the Pi-DigiAMP+

For automatic unmute on boot, add the following lines to /etc/rc.local (before the exit(0))

#Unmute the Pi-AMP+

echo “22” > /sys/class/gpio/export

echo “out” >/sys/class/gpio/gpio22/direction

echo “1” >/sys/class/gpio/gpio22/value


@ALLO_audio_boards @spockfish

Guys any help would be great.

I am not familiar with iqaudio hardware

Sorry Johan my bad…still have the vana combo, but my mind went blank for a min

@Gordon_Garrity Gordon was the one I meant.