Raspberry PI + USB DAC + Mpd + MPad = Great Success
In the main lounge we already have a Nice Yamaha AV Amp, KEF Satelites, and MJ Acoustics sub wired to an Apple Mac Mini running both Plex Media Server and the OSX Plex Client - its a really slick setup using my iPhone or iPad along with a nice Harmony panel remote control it all. Its a good setup for every day. Plex is really slick - I'm a software engineer so it was cool to be able to contribute both the Flickr and Picasa/Google+ Albums plugins to the proejct.
In the smaller room I built up a bargin 2.1 channel setup from a small budget on used items from eBay (I had a cambridge amp from a few years ago so completed the set) - including a Cambridge Audio DAC that I was using to take the optical input from an Xbox 360 - the dual DACs also improved the sound of my v1 640C quite a bit.
The original speakers I had were a bit lacking so I replaced them with a pair of new B&W 685 speakers...
and some mint condition B&W FS700 stands off eBay. Very happy with how it all performs for 2 Channel music - but - I was still lacking a means of streaming all my digital music into the 2 channel system. Plugging my Macbook into the USB port on the DAC and using Plex or ITunes was fine but I was looking for a more permanent solution attached to the stereo.
I wanted something really simple and cheap so I did a bit of research to check that the little Raspberry Pi computer would recognise the DAC Magic as a sound card - the same way a Mac or PC would. Fortunately the kernel of the Linux-based operating system it runs has support straight out of the box which is nice. The little Pi sees it as a 'C-Media USB headphone set' the same as the Mac - you have to do a bit of tweaking to configuration as essentialy the computer has 2 sound cards now - we want all the sound to go to the USB device and nothing to the built-in device.
Using the Analogue out port on the Pi wasn't really an option - plus - the dac can upsample lower sources like streamed internet radio too - a perfect solution for me. It has a wired network port which I use or you can get a USB wifi
If you dont already have have a DAC - there are other USB soundcard options for not very much money (< £15) at all that would be worth giving a try - they have RCA and optical output..
The Pi Model B computer is £26, you'll need a 4gb SD card to run it and a micro USB power supply - and maybe a case (or some lego works well). You can plug it into your TV if you wish via HDMI but I'm just using it for music at the moment so its sat on top of my stereo as I can do everything I need to remotely.
If you go with the standard Raspian image from the PI foundation you'll basically need to install:
* Music Player Daemon (mpd) this serves the music - you tell it about existing music locations - local or network based, tell it which sound card to use and give it a friendly name - for example the model of your DAC
* Music Player Client (mpc) this is a command you use to update your library etc
* Avahi (Avahi Daemon) this is so mpd can advertise itself to other devices on the network. You will be able to access the Pi using its ip address if you don't use Avahi/Bonjour
And thats about it. You could probably disable some more things but playing flac files only uses about 18-20% of the processing power so its not exactly stressed. There is no stutter/lag playing files over 100mb wired network.
You can get some pretty slick client Applications that can control the mpd software running on the Pi - the mpc command line interface isn't slick but it allows you to do everything you need to. MPod for the iPhone/iPod, MPad for the iPad, Android and other stuff is well supported too.
For about £40 all in it doesn't get much cheaper than that really.
Anyone else doing anything similar with a Pi ?
It seems very soon there will be a Plex client for it too which will mean I can plug the Pi it into the TV and hopefully more closely mirror what my Mac Mini in the lounge can already do.