Please help! Can't get definitive answer anywhere! Fiio E7 vs E11 paired with Sennheiser HD25-1 II

If you don't need the DAC, definitely the E11. Better amp and cheaper.

I agree with VDM. If you have no intentions of using the DAC then the only advantage the E7 holds over the E11 is the battery life. The E11 is smaller, cheaper, lighter, and can also be purchased with a spare battery and wall AC charger. It's a stronger amp than the one you'll find in the E7. If you have any plans to use it with a computer the E7 would be a worthwhile choice, otherwise stick with the E11.

If you're looking for something with more bass punch you may want to consider going outside Fiio then. Fiio amps are known to be more neutral than many of the alternatives out there. In the same price range as the E11 you can pick up a JDS Labs Bass Boost Cmoy, as well as a few other choices in the $60-75 range. Not discouraging you from the E11 by any means, but it's something to consider if you really want to add more low end.

make sure you get the L5 line out cable, I use it to connect my NWZ-A845 to my FiiO E6, and there is definately an improvement in sound clarity compared to running through the internal amp, even though I like the sound of the S-Master integrated in the player, having only one volume button to worry about is very nice, I have also noticed an improvement in the players batterylife.. I get about the same playtime using the lineout with the battery saving function of the player turned on, as i did using jack-to-jack with a full charge, so several benefits in addition to sound quality :) Only thing is, that if used with sensitive in-ears, lets say 105dB/mW+, the step from volume stage 1 to 2 is a bit high.. (Edit): 105 isn`t really that high though, hehe