As everyone knows, I wrote the review too late. Now that there is a follow-up Dx3 Pro+, I don't recommend this product. But pro + is a strong recommendation.
In my overall experience, it was a decent headphone amplifier.
I'm using a high-end amplifier and DAC right now, so I won't use it again.
If you want to spend some more money, I recommend you look for the E70v/L70/PA7+ of the topping.