The Topping A30Pro's measured performance is among the best, for those who care about that aspect.

Although it only has single-ended headphone outputs (the 4-pin XLR and 4.4mm outputs are connected to the same circuit and just there for convenience), it has more power than many balanced amps (5.5 watts at 32 ohms), so it can drive nearly all headphones. It is essentially an A90 optimized for single-ended performance (many prefer it over the A90) and with a passthrough instead of a preamp. It does still have balanced inputs so you can connect XLR cables from your source.

I'm the original owner. It's like new (purchased December 2022) and comes with the original packaging and accessories.

My asking price includes the PayPal fee and insured USPS Priority Mail shipping to the US. International will cost extra.

For trades, I would probably only be interested in a full-size headphone. (Especially one with good sub-bass and dynamics.)

Here are some reviews to check out.
https://soundnews.net/amplifiers/he...ro-review-always-outnumbered-never-outgunned/
https://www.audiosciencereview.com/...g-a30pro-review-balanced-headphone-amp.20366/