Are your USB-C gadgets not getting a charge from your PD charger?

This might be common knowledge, but I only learned of This One Neat Trick today, so: I’ve got a bunch of gadgets with batteries that need to be charged. All of them are USB-C these days (thanks, Europe), so I’ve got a spiffy GaN PD (i.e., high wattage) charger with lots of ports that I use for that. But some gadgets, like the Sennheiser Momentum 3 wireless headphones, refuse to be charged by this (or any other) PD charger. But if I connect it to a real computer, it charges just fine. So what’s up with that!? I had just lived with this situation (like an animal) — until today, when I finally did some research. It turns out that the problem is that these headphones (probably) do not have the required resistors that announce to the charger that it’s fine to give the device some power, while the computer’s USB ports always deliver 5V no matter what. But we can fix this very easily: First of all, use a USB-C to USB-A adapter. Plug it into the PD charger. Then take a USB-A to USB-C cable… ……