No, the unbalanced and unbalanced outputs on the 1A/1Z will not function simultaneously. If headphones are plugged into both anyway, the balanced out is active. Yes, and it's because POWER. The power output on the 1A/1Z balanced output is almost 5 times as much as the output of the unbalanced jack. More amplification power = better driven speaker at same volume levels and improved dynamics, or so I've always heard. And listening to the Z1R on my 1A bears that out. I don't think the unbalanced jack's 60mW per channel is enough to do the Z1R justice, and I have to crank it up to get a decent volume. The 250mW per channel from the balanced side though is very acceptable. Not optimal, but I'm fine with it, love it even. On balanced high gain, most of my listening is done at a volume of between 55-70, out of the 1A's max of 120. But I'd really like to hear the Z1R with the TA-ZH1ES amp, which outputs 1200mW per channel. I like being able to move from room to room though, so a stationary amp isn't something I'm likely to purchase anytime soon. This is not to say an unbalanced amp is inferior. But for electrical engineering reasons I didn't study in school, a balanced amp circuit produces much more wattage from the same voltage. That's why it's a great solution for portable use (battery). The WM1A will run nearly as long on balanced as it will on the unbalanced output, but pumping out almost 5x the power. Which means almost any headphone can be driven satisfactorily. Maybe not a 600ohm Beyerdynamic, but almost any. Here's an interesting read about balanced vs. unbalanced headphone amps. The author is emphatic that balanced doesn't mean better sound quality, but he acknowledges the power advantage to balanced for a battery-powered system. https://benchmarkmedia.com/blogs/application_notes/audio-myth-balanced-headphone-outputs-are-better The 60mW per channel output on the 1A's unbalanced output is very suitable for the MA900, btw.