Recommendations for headphones under $400?

My understanding was using Pre-Out completely removes amplification and speaker output from the unit.Don't use Mute,you still have variable output from Hagel to the headphone amp but that shouldn't be a problem,set a level and forget it...

@freediver 
That was EXACTLY my assumption too which is why I was not too worried that it had no headphone jack.
However it does not, anything connected to the pre out is subject to the volume pot level BUT the music is still conveyed via the speaker terminals.
It would need a speaker off option or the pre outs changing internally to line outs.

@noble100 
Unfortunately that is exactly what it says, a DAC loop only.
It would work if all I had was a digital input to the Hegel but it will not work with any of the 3 analog inputs I have.
There was a thread on the very subject back in 2016 with someone having exact same issue.

Maybe the Norwegian designers had not drunk enough beer before thinking this one through.

Yes it is becoming a deal breaker....
Yes I knew no headphone jack but as stated I wrongly assumed the pre outs would do the job

@noble100 
This is whatI came up with, after the event of course!

https://forum.audiogon.com/discussions/troubleshooting-headphone-amp-integrated-amp-connection?sort_...

Sounds like a great reason to put together a complete headphone system.You have the Schiit amp,get yourself a decent little DAC and away you go...Whatever you do don't use tubes on the HE400i's because once you do you will be hooked bad..Mine are driven by the all tube Quad VA-One and it is sublime...I'm considering moving wayyy up the ladder...