Can't get digital signal from iPad?

I picked up a used Topping D50  and was excited to try my old retired iPad as a streaming device.

Hooked up the camera connecting kit adapter to my iPad 2 (30 pin connector) then used a usb cable to the Topping and I get nothing! Well, the iPad continues to play out of it's speakers as if it's not recognizing the adapter maybe?  

Any ideas?
It's supposed to if you use the camera connection kit that converts it to USB output.  It's supposed to provide a pure digital signal that you can then use with an external DAC.

I can hook up a memory card adapter and that pulls up photos app so it's recognizing adapters but not getting anything audio wise.
I think you can only import to the iPad through the camera kit or sync certain other apple products.
You may need to use a powered usb hub (I had to do this with my iPad Air 2) here’s a video that will provide a solution if that is the case.
I'm guessing that's because it's a non powered DAC?  The Topping is plugged into a wall.

I'm wondering if the CCK I got was bad or if my USB cable is from it to the topping is bad.  
What about with a newer iPad that has usb c?

I use the audio Midi settings on my MacBook Air to send a digital signal from a usb a to the usb b on my amp. I’d like to use an iPad instead. Any thoughts?