headphone Amp & Dac for HD650 and computer to 2.1 powered setup

[patton]

Im a novice in the audio world so would greatly appreciate some guidance on a quality DAC with connection to be used for a powered system, and an amplified headphone jack for 300 ohms + (currently have the HD650s on order).  
 
Im currently looking at:

Magni & Modi 2 Uber

Teac UD503
Audeze 301
 
My setup
Sound Blaster Z
AudioEngine A5+
SVS SB2000

Sennheiser HD 650 (on order, let me know if Im going wrong

 
chain
Sound Blaster Z > SVS SB2000 > AudioEngine A5+
 
 
Thanks for your insight and input

 

[pbui44]

Consider also the Schiit Jotunheim with USB DAC add-on for $100 extra:

http://schiit.com/products/jotunheim

The USB DAC add-on is Delta-Sigma, but fully balanced. With the extra cash, you can get a balanced cable for the HD650, so you can get the added power with the balanced connection. If you have a turntable, there is also a phono pre-amp add-on for $100, but DAC and phono pre-amp cannot be together.

Edit: Need a subwoofer out? There is also the Marantz HD-AMP1. Just unbalanced HP only, but speaker taps and subwoofer out:

http://www.rakuten.com/prod/marantz-hdamp1-used-integrated-amplifier/304470250.html?listingId=557724127&sclid=pla_google_OneCall&adid=29963&gclid=CKPcnrK1-dACFQkKaQod3scIYw