I've recently been getting quick, random "buzz" sounds from my 68c, lasting about .5 seconds. I can hear them on my monitoring headphones and they show up in my recordings (Logic Pro). There might be 2 or 3 buzzes in succession, or they might come in longer intervals, like 30 seconds or more, but always just a quick buzzing sound. I haven't had this problem previously.
I've been using my Studio 68c for occasional podcasts and educational audio content for a couple years. Here's my setup. For mics, I'm using both an EV RE20 and a Shure SM7b, Fetheds with 48v phantom power, running into the 68c and then into my 2023 MacBook Pro (M2). There shouldn't be any random power draws on the circuit that I can think of. The electrical outlet is only shared with my MacBook's power brick.
I'm wondering if the AC power adapter for the 68c might be bad? The AC end of the power adapter never did plug fully into the little box that connects to the 68c. That part always seemed like a wonky part of the unit.
Any and all suggestions are welcome!