After researching and reading several reviews of the WA22 by "respected" audio professionals it is interesting to read how they state the balanced HP output connectors impart a significantly higher quality signal. So, given the WA22 balanced connectors are purely for "convenience" and, in fact, are NOT truly balanced, how do they rationalize their statements? Seems to support my long held suspicions...that many in the audio press are no more SQ knowledgeable than the rest of us.
In all fairness to Woo Audio, the WA22 outputs are, in fact, balanced. They simply don't carry a differential signal pair that most folks associate with a balanced audio circuit - and you wouldn't necessarily be wrong in assuming that in today's hyper buzz-word audio world.
As I mentioned in my WA22 post, it is unclear what audio advantage would be gained by employing a differential pair output from the transformers of the WA22.
Given the fact that the 1/4" TRS and XLR outputs are electrically the same, you are correct in wondering how some reviewers can extoll the virtues of one output over the other.
Sennheiser has been in the pro audio industry for decades. They don't make junk and I know they shipped good 1/4" TRS copper with my HD800. I also have a custom 4-pin XLR HP cable wired for amps with differential pair outputs.
I couldn't hear the difference between the two cables with my WA22. Doesn't mean there isn't any, I just can't hear it.
I worked in the pro audio industry for 20 years, and spent a lot of time in recording studios, broadcast facilities, film post, etc. I had the opportunity to work with pros whose ears were a lot more educated than mine, and whose careers depended on having tools that could produce extremely high-resolution, phase-coherent audio. With all the millions of dollars in equipment budgets, I rarely saw anyone use anything more exotic than a $50 Mogami audio cable for equipment connections. Doesn't mean you can't buy bad cables that add capacitance or inductance to the circuit, but once you get to a certain quality, the view was, good copper is good copper.
Doesn't mean there wasn't a difference, they just couldn't hear it.