Upgraded iMac and now loud hiss

I upgraded to a new iMac yesterday, and now my recordings sound terrible. Specifically, I’m getting a loud hiss when I start recording with my Blue Yeti, although it looks like it’s only the one channel. See this screenshot: https://imgur.com/a/DM1VJOV

I’ve also noticed this funky waveform in Premiere: https://imgur.com/a/W0wz0mY

I’ve turned gain all the way down, changed rooms, and removed other recording devices, but nothing works. When I try the mic on my laptop, it’s better.

Anyone have a similar issue? Could it be the USB 3.0 ports? New hardware?

Blue support says: “Sometimes there are compatibility issues with the 3.0 ports and our Yeti because it can supply too much power to the microphone. You can try a USB 2.0 Hub, but it is possible the microphone has malfunctioned. If a USB 2.0 hub doesn’t work I can offer you our warranty services and get you a replacement.”

I’m going to try a USB hub today, but I’m disappointed I have to “downgrade” new equipment.

Any other ideas? I’m using Audacity 2.3.0.

Help me, Obi-Wans, you’re my only hope!

The Blue Yeti is a mono microphone. Try changing all the settings to record mono.