I'll try and give the skeleton of the whole system. Internet is BT, ADSL over copper into the router from which there is a wired ethernet connection looped through the Innuos Zen into a Cambridge CXNv2. Digital output from the Zen is USB into the RME, digits from the CXNv2 are S/PDIF also into the RME. Note the RME has three digital inputs, USB B, S/PDIF Coax, S/PDIF Optical. It has two analogue line outputs, the unbalanced feed an Icon Audio HP8 headphone amp, the balanced feed the balanced inputs of a Quad Artera Pre whose own balanced outputs feed the unbalanced inputs of Icon Audio MB90 mono blocks. These drive PMC 25.23i speakers. You might think that I have one too many amp stages, you would be correct, the RME will function quite happily as a preamp but the current arrangements are such so that mains to the monblocks is easily controlled as they don't have front panel on/off switches. I'm way past crawling around on my hands and knees to use the hifi. The hardest part was working out the where gain should or shouldn't occur, in essence it's all at 0dBu until the power amps which is the right way to do it if you can. Any questions please ask.
Martin