No. The Oppo doesn't charge through the large A connector, only through the micro. The A is for supplying charge when you want the Oppo itself to act as a power bank for something else.
What end of which cable did you connect to what? It's unclear from this description. Also not clear what you're trying to accomplish - if it's charging the Oppo through its large USB A connector, it will never work because the device itself is not built that way.
As far as I can see from my usage so far, the HA-2 will charge through its micro-USB port (labeled "B") whenever it's connected to another device that can supply power and when the micro-USB connector plugged into the HA-2 has a "floating" ID pin (pin 4), i.e. pin not connected to anything, i.e. not an OTG USB-Host type of connector. If the plug has the ID pin shorted to GND, it's indicating to the HA-2 that it should act as USB-Host (which is what OTG cables are supposed to do, normally only at the audio source end = the phone or tablet) and the HA-2 interprets that as "I shouldn't charge from the device at the other end". So what's different between a normal OTG cable and the short micro-to-micro OTG cable that comes with the HA-2 is that the latter has USB-Host connectors at both ends (ID pin 4 shorted to GND at both ends). This allows you to tell your phone to act as USB Host and send music to the HA-2 while at the same time instructing the HA-2 to not charge from your phone.
So a normal OTG cable looks something like this, electrically:
... whereas the HA-2's included micro-to-micro cable has the ID-pin-to-GND thing going on at both ends. This allows you to play music without charging the DAC, and also to plug the cable in either way and still have it work (not possible with a regular OTG).