HiFiBerry Amp 2

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HiFiBerry Amp 2
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The HiFiBerry Amp 2 is an integrated amplifier and sound card capable of playing audio at 24 bits/192kHz. The Amp 2 is a HAT peripheral that mounts on top of the Raspberry Pi, uses the I2C protocol, and powers the Pi through its 5V rail.

Configuration

Note that the following is encapsulated in the autopilot script hifiberry, which can be executed with

python -m autopilot.setup.run_script hifiberry

Device Tree

In /boot/config.txt, remove or comment out the following to disable the built-in audio[1]:

dtparam=audio=on

And add the line:

dtoverlay=hifiberry-dacplus

ALSA

Optionally, you can make the card the default sound-card for ALSA by creating a /etc/asound.conf file with the following

pcm.!default {

 type hw card 0

} ctl.!default {

 type hw card 0

}

GPIO Usage

The following pins are reserved and can't be used for other purposes[2]:

Board Pins BCM # Use
3, 5 2, 3 I2C Configuration
12, 35, 38, 40 18-21 Sound interface
7 4 Mute -- pulling low mutes (so pull it up!)

Specs

Recommend powering with an 18V power supply!

Recommended operating voltage 12-20V
Absolute maximum operating voltage 24V
Maximum output power 60W
THD+N <0.02% typical, output power 0.1-10W
SNR 104db typical
Frequency response 20-20000Hz output filter characteristics depending on specific speaker parameters
Typical output power per channel 14W Vsupply=12V, Rspk = 4Ohm, THD+N <0.1%
18W Vsupply=18V, Rspk = 4Ohm, THD+N <0.1%
20W Vsupply=24V, Rspk = 4Ohm, THD+N <0.1%
8W Vsupply=12V, Rspk = 8Ohm, THD+N <0.1%
17W Vsupply=18V, Rspk = 8Ohm, THD+N <0.1%
28W Vsupply=24V, Rspk = 8Ohm, THD+N <0.1%
Maximum output power per channel 15W Vsupply=12V, Rspk = 4Ohm, THD+N <10%
30W Vsupply=18V, Rspk = 4Ohm, THD+N <10%
44W Vsupply=24V, Rspk = 4Ohm, THD+N <10%
10W Vsupply=12V, Rspk = 8Ohm, THD+N <10%
20W Vsupply=18V, Rspk = 8Ohm, THD+N <10%
38W Vsupply=24V, Rspk = 8Ohm, THD+N <10%
Sample rates 44.1-192kHz