I’m confident that the power supply can supply enough current, but it does look like unpowering other pedals causes some change to the hum. I tried unplugging all audio cables and listening to each pedal individually, and some pedals hum more than others and respond differently to other pedals powering off. Most of them still respond most signifcantly to the H9 being powered off though, as in the hum always goes away without the H9.
