Difference between revisions of "HiFiBerry Amp2"

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'''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  
 
'''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  
  
Efforts to bypass the filter are ongoing. It should be possible to reconfigure the filter if it is a DSP filter, or remove the components if it is a hardware filter. According to the {{#show: TAS5756M | ? Has Datasheet}}
+
Efforts to bypass the filter are ongoing. It should be possible to reconfigure the filter if it is a DSP filter, or remove the components if it is a hardware filter. According to the datasheet ( {{#show: TAS5756M | ? Has Datasheet=}} , page 60) the amplifier is commonly used with a passive LC lowpass filter. 
  
  

Revision as of 22:28, 20 August 2021

HiFiBerry Amp2
HiFiBerryAmp2.jpg
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.

The Amplifier chip used is TAS5756M

Output Filtering

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

Efforts to bypass the filter are ongoing. It should be possible to reconfigure the filter if it is a DSP filter, or remove the components if it is a hardware filter. According to the datasheet ( Tas5756m.pdf , page 60) the amplifier is commonly used with a passive LC lowpass filter.


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