Originally Posted by SaLX
Evshrug.. the only way I can 'define distortion' is solely from what I've read here I'm afraid.
Have a FiiO E5.. whatever card I get (SBZ or ZXR) with the X1, I'll check it out and see how it runs out of both the Line/RCA outs and the headphone out too.. just to see. If it works I will get something better as I will have some cash to burn soon. I'd like to get an O2 amp anyway.
Just to be clear... "Define distortion" was more of a rhetorical question, intended to get you thinking about what distortion can be. For example, EQ could technically be considered a distortion of the original signal.
Basically however, benbenkr already did a great job summing up the deal, where you would prefer using a clean-sounding amp if possible with low THD (pretty common in the regularly recommended hi-fi amps). A noisy amp plus a noisy amp would obviously result in an even noisier final signal, but it has seemed to me to be an additive issue rather than multiplicative. I'm only speaking from experience though, I've had no noise increase problems with FiiO E5, E12, my Yamaha receiver, and my hand-made tube amp, I suppose other amps could have problems but I haven't heard any significant ones from my broad-ish testing.
To those lamenting the loss of headphone HRTF through line-outs: are we sure we can't? If not, it may be tied to the added ability to have both headphones and speakers plugged in at the same time, and switch outputs in-software. That was a requested feature lacking from the Ti HD. Even if you truly can't repurpose the outputs, and even if somehow I've been lucky to hear the only amps that have low distortion themselves and therefore work well double-amping, I would still say double amping the headphone-out is a non-issue because you can go anywhere from cheap amp good with low-impedance cans (the FiiO E5) to a more expensive amp for more advanced configurations (powerful portable, receiver, "exotic" tube amp). Easy problem to overcome the 22 Ohm output of the SB-Z.Edited by Evshrug - 10/17/13 at 3:09pm