I just purchased the Headroom MOH Reference Loop Out (couldn't resist the sale). I got the loop out because I do mostly headphone listening and wanted to have my source directly into the MOH, rather than through an extra inter-connect and my amp. The loop out runs into my amp. Headroom says that if the loop out is on, impedance from downstream may degrade sound quality.

This sounds reasonable, but to reach around and flick that little switch every time I change between speakers and headphones seems like a chore (and the wife will not appreciate it.)

I have two questions for the experts:
1) Does it make that big a difference? and
2) If it does, will turning my amp off during headphone listening help? (i.e. does a turned off amp cause impedance?)

Thanks!