Again, this should not be done but am certain it won't deter some that are still going to try.
This product and its fit into the matrix of the headphone listener universe is interesting to me, even though I am strictly a loudspeaker guy, and I do not use headphones. I admire truly excellent engineering and design, plus the story of an obscure Russian engineer working on his own in China - and outperforming all of the bigger audio electronics companies is fascinating.
I am beginning to see where the confusion comes in when manufacturers of the best audiophile desktop headphone DAC/Amps say things like this (Info is from the Benchmark website, but I did not read the referenced technical paper.):
Audio Myth - Balanced Headphone Amplifiers are Better
September 15, 2016
This Myth Goes Something Like This:
"Balanced headphone amplifiers are better."
"If balanced line-level connections work well, balanced headphone outputs should also work well."
We disagree!
Benchmark does not offer voltage-balanced headphone outputs on any of its products. The reason for this is that a voltage-balanced interface serves no useful purpose when driving headphones. The truth is that a conventional single-ended headphone drive is technically superior to a balanced drive. This paper explains why single-ended headphone amplifiers are inherently more transparent than balanced headphone amplifiers.
But the above is about pro-level expensive desktop gear, and when USB stick-size units are the topic, there are additional limiting parameters. (I am assuming that the E1DA would be most used by laptop owners when not at home or work with their desktop audio systems, which might include components like bigger, more expensive desktop DAC/HAmp.)
Trying to extract maximum performance from a tiny flash-drive size USB DAC/Amp using only the USB low-current 5v power supply would seem to present another difficult set of challenges - and it appears that lacking the HUGE advantage of mains power, IVX has done a tremendous job of working within the limits of the USB stick form factor and power availability.
Now here is a question for you headphone experts - should a budget-minded headphone seriously consider at least two sets of headphones including a single-ended type for home/office desktop use, and a balanced set to maximize performance when out and about using a laptop and a USN stick DAC/Amp?