I tried some more last night, with both players, this time on my surface pro 4 (and still using the mimby plugged into a usb port) instead of the desktop computer downstairs, and was having the same problem. I checked winamp to see if I was using eq and what not, but I didn't see anything checked (if anything winamp is more confusing than anything), so I don't know what the problem is. I don't think I'm using any "special" sound enhancements in Winamp.
I know most audiophiles use JRiver without problems, so I can only assume it's something with my DAC maybe? I tried to re download the schiit driver and reinstall it. It's not like the sound quality is way worse, just subtle. Winamp seems clearer across the board so to speak. I went into the JRiver audio settings and made sure I selected WASAPI instead of direct sound, and went into the JRiver tools menu and selected internal volume, but it still wasn't the same. Maybe JRiver is still running through the windows mixer maybe and degrading the sound? Windows is a mystery as well, lol. My goodness.
I'm open to any more suggestions. Heck, if anyone has the modi multibit or any of the schiit dacs maybe they could download winamp and see if they can duplicate the problem? Or see if they can notice a sound difference on a windows 10 system? Winamp is still a good program and all, but I much prefer the JRiver interface, I like how it's laid out and it's easier to read/navigate, more enjoyable to use. So I hope I can eventually get this figured out. Then again, maybe I'm crazy? lol. Still, we all noticed a sound difference between the two on saturday night, so I wasn't the only one.