USB DAC on OnePlus One issues

I have here an SMSL M2 dac that I bought for my laptop to carry high quality audio on the go and I'm trying to figure out how to get working on the OnePlus One. I've been to XDA Developers and else where looking for solutions, but nothing seems to match my issues.

My OPO is still on 4.4. I hated 5.0 when it came out because it took features away from my OPO like Quiet Hours.

When I plug in the dac to my OPO, it powers the device just fine. When I try to change the volume though, there's only 2 settings it seems, on or off. Using the volume buttons, the volume is either all the way up or down and there's no output.

I read that Android didn't official start supporting USB audio out until 5.0, so is there a driver I need?

I'm trying to get this working with apps like Spotify.

I cant remember if 5.0 has "quiet hours" i was sure it did, but 6.0 does, you could isntall that.

I'll look into it.