I'm using the DX80 also with a Fidelio X2. Volume 90 - 105 on the DX80 / high gain.
I was curious about the DX80 and an amp, so i bought a Heasdstage Arrow 5T. This is a great amp with many positive reviews.
I heard no change in sound because of the surplus of driving power. The DX80 has plenty driving power on it's own.
Mind this: the X2 is known to be easy to drive.
I'm listening on the DX80 with Firmware 1.1.4. The EQ doesnt work correctly in this FW, so i cant EQ the sound. That's where the Arrow 5T is coming in handy: It has great bass-boost and treble boost and works perfectly in enhancing the lesser-recordings (mostly old-skool rock/goth : Soundgarden, Sisters of Mercy and ..).
Of course i tried all the DX80-FW's, and played with the EQ, but i was unable to boost the sound the way the Arrow 5T does: perfect bass-boost options!
But with good, dynamic recordings, i appriciate the DX80 better. It has a bit more air / soundstage, analytical, if you want to call it that, as opposed to the Arrow 5T, which has a slightly smaller soundstage, but a more coherent / musically sound.
So, if i have to believe all the exultant reviews of the Headstage Arrow 5T(P/X), the DX80 is as good or even better, but without any boost-options. To my ears at least, ymmv. And i dont need the extra driving power. (So check out the classifieds
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