RCA (phono) pinout
RCA / Phono Connector Wiring
An RCA (phono) connector has two contacts: the center pin carries the signal and the outer shell is ground and shield. It is unbalanced consumer line level (-10 dBV nominal), which defines both its uses and its hum problems on stage.
| Pin | Signal | Notes |
|---|---|---|
| Center pin | Signal (+) | The unbalanced signal conductor. |
| Shell | Ground / shield | Return and shield; makes after the pin on insertion, hence the connection thump. |
What it’s used for
RCA is the consumer line-level connector: DJ mixers, playback devices, turntables, and the aux inputs of the world. On shows it appears wherever consumer sources meet the rig, which is why DI boxes with RCA inputs live in every workbox.
The same connector carries S/PDIF digital audio (75 ohm coax) and legacy composite video; identical shell, different electrical worlds, label accordingly.
Wiring & termination notes
- Unbalanced means the shield is the return: cable length is hum exposure. Keep RCA runs short and convert to balanced (a DI or an interface) for anything crossing a stage.
- Turntables output phono level, tens of millivolts with RIAA equalization required; they need a phono preamp, not just a level boost.
- Consumer -10 dBV into professional +4 dBu inputs needs about 12 dB of make-up gain; the dBu/dBV converter on this site does the math.
- For S/PDIF use 75 ohm coax; analog interconnect cable often works at short lengths and fails unpredictably at longer ones.
Frequently asked questions
Which part of an RCA connector is positive?
The center pin carries the signal; the shell is ground. There is no negative signal leg because RCA is unbalanced.
Why do RCA connections hum on stage?
Unbalanced wiring uses the shield as the signal return, so any ground potential difference between devices becomes audible hum. Shorter cables, a ground-isolating DI, or balanced conversion are the fixes.