It's hard to explain, but I want to use a guitar amp instead of a headset microphone

I've got a MacBook Pro (2015) and it has no input audio...but it does have a third coection for TRRS jacks to accommodate headset microphones. So I soldered a DIY converter, coecting a quarter inch (amp size) to the microphone ring of a 3.5 mm. I'm sure I did the soldering right because when I plug it into my iPhone it records just fine. But the MacBook doesn't recognize it as a "microphone" and therefore any and all recording comes from the built in microphone. What can I do to force recognition of my guitar amp?