AUNE S17 PRO EVO Discrete Class A Balanced Headphone Amplifier Preamplifier 7500mW 32Ω Silver - reviews - There is 1 review.

I like it
This + ESS dac + brighter linear (studio, reference) sounding mid-high end 300/600 Ohm brighter headphones:

Powerful (300Ohm upto volume 40, 600Ohm upto volume 55 is very loud from 60 total). Detailed. Clean sound - not bright, not cold, with just touch of added warmth, but I would not say it sounds warm. It adds some body to sound (perfect amount). It has smooth sweet lush mids. It does not increase fastness of music - it is touch on the slower relaxed side of sound presentation, but not too much - speed is almost in perfect middle.

Highs are not muffled - they keep the lushness of mids. Bass is nicely shaped and increasedly dynamic. Bass is not too soft. Slam is nicely defined. Bass does not bleed in mids. All frequencies are well balanced but listening attraction goes to mids and later to the balance of everything. Highs are as nicely defined as bass, but everything is lush. You can focus on music itself, not on aspects of sound. The lushness means that it is not overly analytical, but meant for enjoyment.

Space is nicely drawn. Seems natural and wide. Sound placement is nicely recognizable and it is not flat but there is sense of depth. Not too tall.