Bubblecar said:

Good luck.

Should be ok.

And a Google search “can headphone amplifiers be used as preamps” says yes. With considerations to gain and output impedance.

I’m looking around for a seperate high res preamp.

I have been using the high res phone with the PHILIPS Fidelio X2HR Headphones, if I want more ompH, then I use the nx1s between the phone and headphones.

The Philips Fidelio X3 looks interesting.