HiFiBerry Amp2
| HiFiBerry Amp2 | |
|---|---|
|   | |
| Modality | Audio | 
| Part Type | Raspberry Pi HAT | 
| Manufacturer | HiFiBerry | 
| Product ID/Part Number | Amp2 | 
| Product Page | https://www.hifiberry.com/shop/boards/hifiberry-amp2/ | 
| Datasheet | File:Https://www.hifiberry.com/docs/data-sheets/datasheet-amp2/ | 
| Price (USD) | 49.90 | 
| HiFiBerry Amp2 | |
|---|---|
| Uses Interface(s) | I2C | 
| HiFiBerry Amp2 | |
|---|---|
| Uses (Board-Numbered) GPIO Pin(s) | 3, 5, 12, 35, 38, 40, 7 | 
| Provides Backpower | Yes | 
| Computer Card Type | DAC | 
The HiFiBerry Amp 2 is an integrated Amplifier and Sound Card HAT for the Raspberry Pi capable of playing audio at 24 bits/192kHz.
WARNING: while the part is rated up to 192kHz, there seems to be a low-pass filter applied to the amplifier, see here: https://support.hifiberry.com/hc/en-us/community/posts/360014295118-Ultrasonic-frequency-response?mobile_site=true
ICs
- Amplifier: Uses Part:TAS5756M
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 |