Disclaimer: Aune supplied the X7s in this article for the purposes of a Headfonia review. I paid nothing for it. It goes for around 250$ USD. You can find out all about it here: Aune X7s balanced output headphone amplifier.
User-adjustable gain, XLR output, phase splitter, TRS 6,3mm jack, pre-amp: what more could you want in an all-in-one desktop headphone amp? A practical answer to this is lower noise. But as this amp isn't marketed at the portable audiophile, it is probably fair to shelve that desire.
The X7s is powerful, and unloaded, spits a signal as free of THD as I've seen. Loaded, it trips up under the stress of multi-armature earphones. It gets back to its feet once you plug headphones in.
It is crisp, detailed, and ever so slightly warm sounding. If you've got 250$ burning a hole in your pocket and don't have a headphone amp, check this bad boy out. If you're interested in checking out balanced output, but don't have the dosh to purchase a LinnenberG Maestro, by all means, check this thing out. Just know, because of off-kant phase, high levels of line noise, and aggressive gain even at its lowest setting, the X7s is next to pointless with IEMs.
Otherwise, not bad.
The following Rightmark Audio Analyzer tests were conducted through this equipment.
Source: Chord Mojo
ADC: Lynx Studio HILO LT-TB
Computer: 2012 27" iMac
Cables: 1,5m Hosa Pro 3,5mm stereo to dual 3-pin XLR (around 8$)
NL - no load
SM2 - Earsonics SM2
S7 - Audio Technica ES7
DT880 - Beyerdynamic DT880
24-bit TARGETS and loads (+6dB)
24-bit summary (+6dB)
The X7s is an easy to use, powerful amp with a whack of features for its price point. It looks good atop a desk. It looks good atop a nice HiFi. And it's got the goods for most headphones out there. I don't recommend it for IEM users.