I've been playing with the Raspberry Pi again recently, this time wanting to create a very straightforward AirPlay compatible receiver. The idea was to take the Model A, connect via wifi on it's only USB port and use the line out jack to a little amp.
Well, I've made it and it works, but good grief! The audio quality out of the Pi is just awful, to the point of being useless. Running the output at 95% prevents clipping, but when the input signal is quiet there is so much hiss it's unbelievable. As the signal comes in quietly, it is distorted. Only when the signal is strong can you get away with using the output, but then as a song fades out, all the problems become obvious again. It also varies considerably between power supplies; the PSU I thought was bad was actually better than any of my others, all of which made the background noise levels worse.
Of course, you can get around all of this by using an external audio device. But not if you're using a Model A with it's single USB port and need a network connection. And you can't use a HiFiBerry either; not enough GPIO pins (plus, it more than doubles the cost of the unit).
I know the Joggler's audio circuit isn't the best in the world, but it's downright audiophile in comparison.
Update: Trying this on some much more forgiving domestic audio kit now and it is acceptable, but if I was having to rely on the volume adjustment of the Pi, I'd be scuppered. So long as the audio output level from the Pi is high and fed into a nice low-resistance input, you're okay. But turn down the Pi and turn up the amp output and you'll be very surprised at what the audio sounds like.
