It's Balanced input > Unbalanced Output
I think Balanced is not that important as an output, Amps these days masures really well that it does not need a balanced output to decrease distortion and pumping extra power, it's 5.5W already that's more than enough for 95% of headphones.
Topping really misjudged the price on this one. Gustard H16 runs circles around it - it's fully balanced with remote, a true preamp function, r2r volume control and only $50 more...
The Topping A30 Pro actually measures quite a bit better in real world specs than the Gustard H16. Not just in the basic specs of getting to 4v output, THD+N, and SINAD, but in the actual distortion vs power tests the Gustard was kinda bad. Medium gain is the only setting you can have good specs with on the Gustard, but even at that setting the A30 Pro blows it away and at WAY higher power output.
https://www.audiosciencereview.com/forum/index.php?threads/topping-a30pro-review-balanced-headphone-amp.20366/
It says that the input is passed through when the power is off, but what does it do when the power is on?!?
I would like to put this as an insert between my main XLR stereo outs and my studio monitors. Ideally it would pass the input through to the TRS output continuously.
Any insight into this wound and and I think
it is only a passthrough output, no preamp ability. you would have to control the volume at source or the monitors. as it is a passthrough design i would assume (can not personally verify) that even with headphones plugged it the signal would carry on, no headphone cutoff circuit.