Question on order of connection for headphones

[brlawyer]

Apologies if this has been answered elsewhere, but my question is fairly simple. Here is my setup:

 

- iMac 27" 5K 2015 with mostly lossless music (ALAC) on iTunes/Audirvana;

- Marantz HD-DAC1 DAC;

- Denon DRA-F109 amp/receiver (connected to B&W stereo speakers and Planar turntable).

 

I am about to purchase new (most probably open back) headphones, probably the Beyerdynamic DT-1990, or the closed back B&W P9.

 

I could not find the exact answer on Google, so here it is: WHERE should I plug my wired headphones, particularly if they are of high impedance? To the DAC directly, or to the Denon amp? So far I have used them directly with the DAC, but realize that this may not be very convenient, as the amp is the end device for all other outputs...  

 

Tks!  

[WAM]

The Marantz is a headphone amp, so I should try the Marantz. 

[audiobomber]

You can try both, but I would expect the Marantz to be a lot better.