Found this article regarding balanced headphone setups. I found this interesting, as Rob Watts from Chord pretty much eschews balanced headphone amps in their gear.
https://www.headphonesty.com/2025/09/engineers-reveal-balanced-headphone-amps-pricey-gimmick/
If single-ended can adequately drive your phones, then it’s all you need. The added complexity of balanced doesn’t necessarily equal better sound.
For some manufacturers, the challenge of engineering a balanced circuit is great fun, whether it’s actually better sounding or not. The also-included single ended circuit probably gets neglected in the engineering efforts, so it may end of the ugly stepchild in units that offer both single-ended and true balanced.
To my ears, with lower to middle tier equipment, balanced can reduce unwanted cross-channel interference and improve clarity. I found genuine value back in the day when trying to manage treble noise with my HD 600, and did a lot of back-to-back testing.
With higher tier stuff, balanced may only increase power. Also, XLR cable connectors are built heavier and tend to have more consistent dimensions than often loose-fitting RCA and TRS connectors. That’s a small advantage.
An issue that doesn’t get much mention is that dacs which are implented as balanced often perform better that way. Using a balanced amp, even if the amp itself does not benefit, might give better results than using the single-ended dac output.
It’s a way to solve a problem in a circuit, balanced designs cancel out some classes of noise in a circuit, for a high feedback SS design, that’s not really buying you very much, possibly some PSU noise cancellation.
In tube amps it’s a bit different, they generally have very little feedback, as tubes got smaller, they amplified less linearly, it was mostly 2nd harmonic distortion, and 2nd harmonic distortion is cancelled out in push pull designs. Look at the distortion/ power figures between a push pull EL34 amp and a single ended one. And they do sound very different.
It’s a trade off like anything else in amplifier design, it’s not inherently better or worse.
Over the years my system has been at versions points, entirely balanced, and entirely SE, it’s currently the latter, but it has more to do with how the components sound than balanced vs SE.