I've mentioned it in passing before, but since I'm about to build the beast next week on my vacation, I figure I'll detail the design here. Let me start with the overview and then the block diagram of the overall system.
Simply put, the design is simply a costly HTPC focused on audio performance. The core is a Windows PC, driven by a power adapter fed from a laptop power brick. The audio is converted by an audiophile grade AKM4495 dual mode DAC (one DAC per channel to reduce the noise floor). That output is fed into a Burr Brown PGA2311 preamplifier, which is a single chip stereo analog solution controlled digitally. The controller for this will be an Arduino based board, written by me. Here is the block diagram:
The deck requires an annoying three power supply solution. I avoided using a single R-Core for the DAC and Preamp because I'd rather buy the toroids from AnTek.
If you notice, I've chosen to use a splitter to pull the PCM audio from the HDMI feed rather than use a usb connection. This is a choice I made to make the audio experience more transparent, since any device on the HDMI output end will get the same audio feed that the high end output gets, without having to switch any settings in the windows software.
Two additional RCA, line-level inputs all the preamplifier stage to act as a preamp for other attached devices.
The back panel will offer: 2x USB 3.0, 2x USB 2.0, HDMI, Gigabit Ethernet, Wireless N antenna, RCA analog out, 2x RCA analog in. The nice thing about the USB and analog in, means direct level-matched comparisons between USB external DACs can be easily made.
The whole device will be controllable via a 2.4ghz wireless keyboard/mouse, as well as via webpage using local network and devices such as your phone.
The clincher: If I can get the programming for the arduino right, and rig up a simple quality MIC, the preamp stage will be able to automatically level match for DIY events.