Allo Sparky – and his magic Piano 2.1 HiFi DAC


The Allo Sparky SBC

The Allo Sparky SBC is a quad core single board computer, with similarities to the Raspberry Pi. We recently received a package containing a Sparky board and a number of other Allo boards which complement the Sparky.

Allo Sparky SBC

Allo Sparky SBC

The boards we received were:-

In addition, the package we received also contained a power supply, a micro SD card (loaded with a version of the Sparky SBC operating system), a bag of assorted black nylon spacers and screws, and an Allo CM (Capacitance Multiplier), which is designed to condition the power supply to the audio amplifier.

The contents of the kit we received is intended for the construction of a quality audio player, so we decided to see what we could make of it.

Setting Up

The boards all slot together nicely, with the help of the black nylon spacers. The Kali reclocker board fits on top of the 40 pin GPIO header of the Sparky SBC board. As well as a 40 pin GPIO socket on the underside of the board, the Kali reclocker board also has an extended 40 pin GPIO header on the top side of the board, so the Piano DAC board sits on top of the Kali board using the same 40 pin GPIO header arrangement. Finally, the Volt amplifier board sits on top of the Piano DAC using 2 sets of perpendicular headers and sockets.

Having fitted the boards together, and screwed in spacers and screws where required, the Volt amplifier board has to be wired up to a set of speakers. The screw connectors on the Volt amplifier board are a good size, so it’s really easy to fit some nice chunky speaker cable. I soldered the ends of the cable first just to prevent the copper strands from fraying. Additionally, the Sparky SBC board needs to be connected to a monitor using an HDMI cable, and a keyboard and mouse need to be connected to 2 of the 3 USB sockets of the Sparky. Incidentally, one of the USB sockets on the Sparky SBC supports USB 3, which is really useful if you want to connect a USB 3 hard drive for faster disk access.

Finally, the micro SD card needs placing into the SD card slot of the Sparky SBC board, and the whole set up needs to be powered up. The Kali reclocker board is connected to a 5V power supply which powers the Kali board, the Piano DAC, and also the Sparky SBC board. However, the Volt amplifier requires a separate 19V power supply which is actually supplied via the Allo CM board (to help smooth out the power supply). The documentation for the boards states quite specifically that the 5V supply should be switched on before the 19V supply, and that when powering down, the 19V supply should be switched off before the 5V supply.

Once booted, the Sparky runs up a Ubuntu desktop, from which it is possible to run Kodi. Unfortunately, the vesion of Kodi installed on the SD card did not seem to offer support for the Piano DAC, so it was not possible to select the Piano DAC as an audio output device.

The SD card also has Max2Play installed. However, the version installed also did not seem to provide support for the Piano DAC.

Raspberry Pi Support

Fortunately, the Kali reclocker and Piano DAC boards are pin compatible with the Raspberry Pi 3 board, so I decided to swap out the Sparky SBC, and replace it with a Raspberry Pi 3. The Sparky SBC web site provides links for downloading documentation, and software images for both the Sparky itself and the Raspberry Pi; so I decided to download the Max2Play image for the Raspberry Pi and to give that a try.

Burning the Max2Play image to micro SD card is the same process as for burning any other Raspberry Pi image, and can be done using Win32DiskImager or Etcher, remembering to first format the micro SD card using SDFormatter.

Once booted, the Pi runs up a Max2Play desktop which does give the option of running Kodi. Again, however, as with the Sparky SBC image, the installed version of Kodi did not give the option of using the Piano DAC as an audio output device.

Fortunately however, the Max2Play web interface did allow the Piano DAC audio device to be used as an audio output, so once Max2Play Music Player (MPD) had been configured, it was finally possible to blast out some sounds from the speakers.

The images below show the setup of the Allo boards fitted to the Raspberry Pi 3.

Raspberry Pi 3 and Allo Boards

Raspberry Pi 3 and Allo Boards

Raspberry Pi 3 and Allo Boards

Conclusion

The audio output from Allo Piano DAC and Volt amplifier is excellent. We had our Volt amplifier wired to a reasonably decent set of speakers using some fairly chunky speaker cable, and this gave a really solid sound. The only real down side of this set up seems (currently at least) to be the fairly limited software support. However, we fully expect this situation to be resolved fairly soon, when we’ll hopefully be able to try out a bigger range of software solutions, as well as being able to run on the Sparky SBC board itself.