I don't look at the position of the K7 volume knob. I use my ears to tell me when I have the correct volume ;-)
I like the K7 a lot. Works well with everything I've tried with it so far.
The light can be annoying, but as long as you aren't facing it in a blackened room, it's not really an issue.
“They lie about marijuana. Tell you pot-smoking makes you unmotivated. Lie! When you're high, you can do everything you normally do just as well — you just realize that it's not worth the fucking effort. There is a difference.”
― Bill Hicks
I had the baby UP2, which I liked a lot (until the control/volume wheel broke). Never used it as a USB DAC, but it was very competent for mobile use with Bluetooth. I understand the test suite needs to be consistent across all tested products, but as Shanling has stated, the main purpose of this...
Could be that I'm only testing the likes of Xiaomi, Chuwi, Aldocube and older Sony devices. Some with LineageOS. Never found one that worked. Maybe the more expensive stuff from Samsung is supported, therefore I stand corrected.
I also have the Tempotec Sonata BHD (the dual DAC balanced version of the Pro). The volume steps are much better on this than the Pro. Another excellent product and better for driving more demanding high impedance ear buds. The price performance ratio of these dongles is outstanding.