If you want to try something for no cost if you don't like it.
Your MyDac has very low output impedance at 2v output, you may get the best/transparent sound using this $49 passive pre instead. For $49 it's worth a try, and it comes with a "15-Day Money-Back Guarantee"
http://schiit.com/products/sys
A Quote from the master Nelson Pass
"We’ve got lots of gain in our electronics. More gain than some of us need or want. At least 10 db more.
Think of it this way: If you are running your volume control down around 9 o’clock, you are actually throwing away signal level so that a subsequent gain stage can make it back up.
Routinely DIYers opt to make themselves a “passive preamp” - just an input selector and a volume control.
What could be better? Hardly any noise or distortion added by these simple passive parts. No feedback, no worrying about what type of capacitors – just musical perfection.
And yet there are guys out there who don’t care for the result. “It sucks the life out of the music”, is a commonly heard refrain (really - I’m being serious here!). Maybe they are reacting psychologically to the need to turn the volume control up compared to an active preamp."
Cheers George