So to clarify, if I want to use an external DAC/Amp combo, can I just get a cheaper card with the processing I like and an optical out? For example an SB1040 to do CMSS-3D Headphone into a Magni/Modi? Or wait, Modi doesn't have optical in... so I'll need a soundcard with RCA outs or a DAC with optical in. That sound about right?
EDIT - Duh, sorry, Modi is USB-in. RCA-in is on the amp. I'd have to use something like a E17 DAC with SPDIF input or a E07K DAC with 3.5mm input using "What U Hear" from the sound card. Does that make your heads hurt less?
EDIT 2 - Okay now I'm confusing myself. If I use the What U Hear thing, that's already analog and don't need a DAC, right? So yeah, a DAC with SPDIF seems like the only way to use the sound card as a DSP with an external DAC/Amp.
Check out the Audio-GD NFB-15.32 or NFB-11.32 external DAC/Amp, they come with S/PDIF (optical & coaxial) input connections.