Hello, I can't decide which amp to go, between Audio-GD NFB 11 and Topping DX7. One thing I prefer NFB11 is, it has an output select switch on the front, to switch headphone amplifier and pre-out. It's a bit dangerous that one click over could make the pre-out as fixed level out, which may blow my speakers out. How does DX-7's output selection works? I saw buttons on the remote, but looks not so straight forward, and even read that the output volume isn't adjustable?? Please let me know, you owners, how the switching between headphone out and pre-out works. Thank you.