Should work fine. Depends on the quality of the headphone amp in the pioneer.
I have my DA-131 plugged into my Stereo NAD c740 amp and have noticed a very big improvement through my speakers (which I was beginning to doubt were a good match with the amp), and the headphone amp in the NAD is all I would need I think, very good quality in my opinion.
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*Iriver H120 (rockbox)mp3 player with Px100/ Westone UM1 for portable use.
*Nicely burned in (years) HD280pro for work
*Er15 earplugs for work
*Cmoy Amp (hardly used, dissapointing)
*Ubuntu PC -> HAGUsb -> Keces DA-131 -> NAD c740 -> Wharfedale Diamond 9.1
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