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?
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?
You might remember Wadia made ipod docks several years ago that did convert the digital signal into the dock, which had a DAC built in.  It also worked with ipads.  I had one of those so I know it's possible to do this.  Might be something quirky with the Topping DAC.  Sorry I can't be of more help.
30 pin does not do output just input, I found out myself by trying the method with my iPod iTouch 3.1.1 operating system plug in to a Schiit Bifrost 2