[Rotmammoth]

Hello, I have a FiiO E10 and recently bought an O2 amp to power my Sennheiser HD 650. I'm probably not doing the HD 650's justice, but that's all I can afford. 
My concern is how I connect the E10 with the O2.  Can I just use a 3.5 to 3.5mm jack to connect the two through the E10's line out and the O2's input slot?  I noticed that when I do this, the bass boost on the E10 doesn't work, meaning only the O2 is working as the amp and the E10 as the DAC right?
Would gladly take suggestions on this setup.

Thank you

 

[Rotmammoth]

bumpzors
 

 

[shadow419]

You are correct.  That's all you really have to do, and the O2 will power the HD 650 well.