If you have some old stereo speakers stored away in your basement, chances are they connect through the old way—with wires—to an amplifier, and that is the reason they were banished to the basement. With HiFiBerry Amp+ and a single board computer, such as the Raspberry Pi (RBPi), you can resurrect your vintage speakers. Using the latest in open source technology, you can now use the renovated loudspeakers wherever you want, since they now operate wirelessly.
HiFiBerry offers their Amp+ as an amplifier for the RBPi. As it is a Class-D power amplifier, it is highly efficient as a stereo module, and you only need to connect the loudspeakers. This high-quality amplifier is ideal for setting up multi-room audio installations.
The amplifier is stable enough to drive 4-Ohm loudspeakers and those with higher impedance as well, pumping out 25 W of output power. However, the best part is the RBPi can fully control the amplifier. As the amplifier includes on-board digital to analog converters, you do not need external sound cards or DACs to provide the 44.1 KHz and 48 KHz sample rates. The board connects directly to the RBPi without needing additional cables, and this provides a full digital sound path for optimal audio performance.
The HiFiBerry Amp+ comes as a pre-fabricated kit, so it needs no soldering. It is a daughter board for the RBPi, and when the RBPi plugs into it, you need to connect only a single external power supply of 12-18 V to supply both the amplifier and the SBC, as the RBPi draws power from the Amp+. You can use the Amp+ with all RBPi models that have the 40-pin GPIO connector. The board sits on four small plastic spacers that come with the kit.
The specialty of the Amp+ kit is it converts the digital signal into audio with far greater clarity than the RBPi can, and delivers that to the speaker as a 25 W audio amplifier. On the reverse side of the board, the female connector is easily visible, so it is easy to plug in the GPIO pins of the RBPi.
On one side of the board are a jack for powering the board, and six wire-terminals. If for some reason you cannot use the jack to power the board, use the two wire-terminals on the left. The rest of the four wire-terminals are for connecting to a pair of stereo loudspeakers, using two audio cables per speaker.
As the board takes in 12-18 V supply and delivers power to the RBPi as well, it is important to not power the RBPi from its usual 5 V power supply. This reduces the number of wires to the assembly. As the Amp+ board is very small, it does not protrude beyond the RBPi. It is important to mount the board on the four plastic spacers to avoid breaking the GPIO pins.
The SD card for the RBPi can be of the 8 GB type and people have reported better performance with Transcend cards. However, you can use 16 GB cards as well.