This is similar to how it is on iPad's, they also won't accept it directly. There is a chip inside the USB hub so the phone sees the HUB first and then gladly accepts the DAC connected to the HUB. We don't have any solution to this issue unfortunately, except that you could look for a smaller hub, or modify that one (remove the unneeded connectors).
about 3 years ago
My problem is that I can only get it to work using a usb otg hub like this one:
rather than the simple adapter type cable. There are no issues with the dac itself and I'm very happy with it but these hubs are bulky to carry around together with a phone, amp and dac and are prone to breaking very easily-I'm on my 4th one at the moment. USB audio tester just shows a jumble of letters when I use any "regular" adapter but shows the manufacturer etc with the hub connection. I'm using a Sony M2 but interestingly, I tried it on my friends Samsung with a normal adapter and it worked fine straight away. Any ideas?