Almost always because phantom power is switched off. Most condenser microphones need 48 V sent from the interface up the XLR cable, on a button usually marked 48V or P48.
Check in this order
Phantom power. The 48V or P48 button on the interface. This is the answer most of the time.
The input. A microphone plugged into a line or instrument input produces almost nothing. Use the microphone side of the combo socket.
The gain. At zero, a perfectly working chain is silent.
The cable. XLR end to end. No adapters in the middle.
The software. The interface has to be selected as the input device and the track has to be armed.
The one caution
Phantom power is safe for most microphones and not for every one — some ribbon microphones in particular. Check the manual for your model before switching it on, because the manufacturer’s instruction takes precedence over any general rule.
Check your own manual before you plug anything in. Voltage, polarity and current draw differ from model to model, and the manufacturer’s figures take precedence over anything written here. A supply of the wrong polarity can damage a pedal in seconds, phantom power is safe for most microphones but not for every one, and the required voltage is printed next to the socket or stated in the manual — not inferred from a connector that happens to fit.
The questions players ask
Do dynamic microphones need it?
No. Dynamic microphones generate their own signal and need no external power, which is why one will work on the same cable and interface where a condenser stays silent.
Can I get phantom power from an adapter?
No. An XLR-to-jack adapter passes audio but not phantom power, so a condenser plugged in that way stays completely silent.
Last reviewed 2026-08-18