Hey I've attached a video for better understanding.

I'm basically trying to get audio from my Duet 2 into my Iphone. This worked great with my firestudio, but I can't figure it out with the duet. Maybe I need a headphone amplifier?

The firesatudio had "general purpose outputs" that worked great. I would work in Pro tools, send my master bus to those outputs and run it into my iphone. This worked great as I record a lot of instagram videos and get all the efffects from protools running straight into the iphone while I record video.

Can't seem to get it working with my Duet 2, though :(
There are no "general purpose outputs" so I just ran the exact same cable rig from the main outs (instead of them running to my monitors) into my iphone. But this doesnt seem to work. Just a lot of distoertion, static etc.

What would be different with the main outputs on the duet vs the general outputs on the firestudio?

Any help is appreciated. Thanks.

VIDEO FOR MORE EXPLANATION: https://youtu.be/sLyYkuk_hTo