[Miguellacorte]

I'm currently looking of an audio interface that has the guts to get the senns hd800 to its max potential. I'm looking to pay up to 1600, much better if less. Can the apogee duet do so? Is there a difference between apogee duet and quartet? I have also the genelec m040 so the audio interface/headphone amp should be caple to handle the speakers. 

 

[maeveth]

Probably best to keep your threads consolidated but here is some info for you anyways
 
If your trying to get a DAC/Amp combo for $1600 USD you not going to be able to drive the cans to the "max" but you can get pretty close.  I really liked the Oppo HA-1 that I've heard at a recent CanJam, $1200, looks nice, pretty small.  It has pre-outs so you can connect it up to your Genelecs as well since you already have a pair of powered monitors.
 
Some notes form me on my short session with it though... compared immediately to a Rag/Yggy combo on HiFIMAN HE1000s.  The HA-1 had a slightly smaller sound stage presence and the bass was not a crisp but it was still very good.  The Yggy/Rag combo is particularly good at pointing this out due to the "Moffat Bass".  I did also listen to both with the HD800 and the notes are the same really though everything was a bit better to my ears with the HE1000.
 
For reference the Yggy/Rag combo is $2300+$1500 so its well out of your stated price range meaning the HA-1 is excellent value for you.  I had considered getting an HA-1 prior to ordering a Liquid Carbon to hook up to my existing Yggy.