Your condenser microphone needs power. Phantom power, and that means 48 volts of direct current gets sent down both pin 2 and 3. Because there’s no difference across those two pins, there’s no current when you measure across them.
It’s when you measure against pin 1, which is the ground, you’ll see the voltage. That’s why we call it phantom power, because your dynamic mic can safely ignore that current. But it’s important that everything be connected the right way, because if not, particularly with something fragile like a ribbon mic, the results can be catastrophic.
Aside from locking in place, this is where an XLR cable has an advantage. Because it’s all on one plane, pin 1 always connects to pin 1 on an XLR, but not so with TRS. This can be a real issue in studios where microphone signals are often routed through a patch bay.
Because as the three connectors get inserted into the TRS jack, the tip, which should be pin 2, connects to the sleeve, which should be pin 1. The connections are made in properly twice before they land in place. Which is why in your little black book of best practices filed under order of operations, it should say, “plug in the microphones” before you engage phantom power.
And you can show that with someone who belongs in a Beat Kitchen glass.
