Tag Archives: raspberry pi

A standalone streaming media device based on Raspberry Pi and HiFiBerry DAC

This is the most advanced HiFiBerry DAC setup we have seen so far. A German user integrated not only the Raspberry Pi and the DAC in a nice enclosure, but also a switching power supply. Power is connected using the onboard header on the HiFiBerry DAC and a USB WiFi Dongle is used for wireless connectivity.

IMG_2336IMG_2334 IMG_2333 IMG_2332

Class-D amplifier on the Raspberry Pi

The first test setup of the new Class-D amplifier project works. We have a fully digital connection between the Raspberry Pi and the amplifier. With the right driver (we have to work on this first), volume and also sound processing can be controlled directly from the Raspberry Pi.

class-d-test

Note: Don’t try to connect the output of an Class-D amplifier to an oscilloscope unless you know exactly what you’re doing. Many Class-D amplifiers use H-bridge outputs. In this case none of the output connectors is directly connected to ground. Connecting one of these pins to the ground of an oscilloscope can create a short-circuit and destroy your circuit and in worst case even your oscilloscope!

FIR filtering on the Raspberry Pi

hbdigi-proto-raspberry

A HiFiBerry user asked, if it would be possible to use BruteFIR for room equalization with the DAC. I was pretty sure that BruteFIR only runs on Intel CPUs. Looks like I was wrong. It seems, that BruteFIR also runs on the Raspberry Pi. Alternatively JConvolver also implements FIR filtering on the Raspberry. One commenter noted, that he has a setup running BruteFIR with 32k taps and 50% CPU load on the Raspberry. Wow! This is something we have to look into. Using the HiFiBerry Digi with an additional SPDIF input would allow to use the Raspberry Pi as a flexible room-equalization module.

Has anybody implemented a setup like this already? Let us know!