PlainAMP setup

Please make sure that you have read and understood the disclaimer at the bottom of this page before you continue.

 

Before you start

Your PlainAMP maybe just arrived and you want to start with setting it up immediately.
There are some things you should know before using it.

  • you have several options to power it
  • you may like to start with 5V although this isn’t recommended for best sound quality
  • choose 12 V for medium sized speakers and 24 V for large ones
  • never remove the power while music plays
  • if operating it between 12 V and 24 V care for good airflow
  • if you discover a little background noise scroll down and read the volume control section

 

Hardware

  • connect the most important pins of the PlainAMP 16 pin connector to your SBC
  • this are at least: BCK, LRCK, DATA, SDA, SCL, GROUND, 5V
  • solder or crimp some flat connector female sockets to your speaker wires
  • plug in your speakers wires to the four flat connectors
  • connect the large power supply flat connector to either 5V of your SBC or to an external power source
  • in case of an external power source you also need to connecter its GROUND to the PlainAMP

 

 

Connection example using Raspberry Pi and 5V

[table caption=”” width=”400″ colwidth=”30|20|80|20″ colalign=”left|left|center|left|right”]
PlainAMP,pin,Raspberry, pin
5V,1,5V,2
GND,16,GND,6
SDA,14,SDA1,3
SCL,13,SCL1,5
BCK,7,BCK,12
LRCK,5,LRCK,35
DATA,6,I2S-DOUT,40
MCLK,8,GROUND,9
POWER,flat,5V,4
[/table]

 

Software

  • PlainAMP requires either a suitable MCLK or configuration through I2C
  • without connecting pin 10 and pin 2 it has the I2C address 0x4c
  • it is compatible with the “IQaudIO DAC” driver in case of a Raspberry
  • simply add following line to your /boot/config.txt
    • dtoverlay=iqaudio-dacplus
    • save, exit and reboot
  • if you now enter “aplay -l” in your command line there should be a new sound output

 

Volume control

PlainAMP is on the hardware side configured to work in +26dB mode (maximal amplification).
In specific setups this can cause very minimal background noise when hardware volume control is set to 100% and you use software volume control to regulate the volume.

This behavior is totally normal and also applies to other class-d amplifiers / designs with I2S input. Therefore it is always recommended to use the hardware volume control through ALSA.
This can be either done using alsa-tools like “alsamixer” or by telling your audio program to scale the volume through the alsa driver.

If your audio application doesn’t support hardware volume control:

  • open “alsamixer” and set the “analogue” control to zero (-6dB)
  • It is also recommended to reduce the digital volume by a few steps

In case you have a SBC without alsa drivers for PlainAMP you can use our cmdline program for this.

 

Disclaimer
Although we have taken great care during creation of this guide we cannot give you any guarantee on their completeness and correctness. We are not responsible for any direct, indirect, incidental or consequential damages resulting from following this guides. Furthermore there is always the risk that something on the side of your single-board-computer (SBC) was changed recently which is not taken into account here.