XLR Input: Balanced, Phantom and What Fits
An XLR input is defined by what it expects: a balanced signal, sometimes phantom power, never a raw speaker feed.
Quick Answer
| Input type | Expects | Phantom |
|---|---|---|
| Mic level XLR | Balanced microphone signal | Often, switchable |
| Line level XLR | Balanced line from gear | No |
| Instrument through DI | DI’s balanced output | Per DI spec |
| Adapter fed | Unbalanced converted | Never for cheap adapters |
Balanced Signals
Three conductors
Two carry mirrored copies; the input subtracts noise picked up en route.
Long runs
Balanced lines stay clean for tens of metres, unlike RCA.
Phantom power
48 V up the same cable powers condenser mics. Ribbon gear needs care.
Unbalanced plugs in
TS to XLR adapters work but forfeit the noise rejection; keep them short.
Using XLR Inputs Well
- Match mic versus line level to the input’s gain range.
- Engage phantom only for mics that need it.
- Use DI boxes for instruments into mic inputs.
- Check pads when hot signals overload.
- Label stage inputs by channel, not by plug type.
Real-World Applications
- Live mixing consoles.
- Audio interface inputs.
- Powered speaker feeds.
- Studio microphone chains.
Related Guides
For wiring detail, read XLR connection guide. For selection, see XLR mic cable guide. For the connector map, start with audio connector types.
FAQ
What is phantom power?
48 V supplied through the XLR to power condenser microphones.
Can I plug a guitar into XLR?
Not directly. Use a DI box or an instrument input.
Why is XLR quieter than RCA?
Balanced signalling subtracts picked up noise.
Does phantom harm dynamic mics?
Modern dynamics tolerate it; ribbons with care.