Not at all. Output impedance is more important at the last gear that drives the load, that means your headphone amp, not the sound card. The typical number of impedance for source to amp connection is that the output impedance of the source should be about 10x less than the input impedance of the amp, or in another word, the Titanium HD output impedance should be 10x less than the input impedance of magni. That should be fine as most amp have over 10k ohm of input impedance.
8/11/14 at 8:23pm