Design looks great, although I like the symbols more from can dude regarding input selection. I find input selection very important, because as far as I know there is some idea that all unused ports will be switched off with audio-grade relais to avoid any electromagnetic interference (emi) to the dac on all unused ports.
Sure the auto-switch would work but even the autoswitch would get confused over time if leave toslink from my radio and spdif from my cd-player and the usb-cable from my computer all connected and I do not switch off everything I do not use or if I switch off I always have to do it before switching on the other unit or some ripple and noise will be induced to the dac and a big plop will be heard on the speakers or anything like it. Way to complicated. As well in the x f a I ordered I do not want any - even unused - cable to destroy the hard earned money bought THD and SNR on my dac by induced electric disturbance on the other ports. So for the simple pulse I do not really know, but for the x f a I hope this is integrated. Why buying a sub 1.0uV regulator feeding a femto-clock feeding dual-dac if all cables have direct access - even with galvanic isolation - to the circuit. Just imagine not you but somebody else in the house turns on the device that feeds some of the other ports. Or you want to plug or unplug on any port while the device is converting on the other without hearing any plop on the speakers. Only possible with relais or a manual switch and some sort of sign to be sure which one is playing and used and which are good to go. Audio-grade 4-position switches can get quite expensive so maybe this is the reason why all electronic, as well the relais can have a better position on the pcb I guess immediately after the input.
I hope our units will feature off-switch relays on all unused inputs and therefor we would need some sort of understanding which input is used. Some years ago we would have got a rotary switch with 4 engraved symbols like most hifi features, nowadays we have relais and electronic status symbol leds I guess. Do you know the old braun radios, they have nice simple round dials. Total analog! Maybe a "cheap" 4-position switch could be used not for the audio signal but to switch the relais! How simple would be that, then no need for led, but only laser the names or symbols on the plate. Only Larry Ho can tell.
Is anybody in geek force to get this straight if I am wrong?