Turntable phono output carries a very low-level RIAA-equalized signal (2–5mV for MM cartridges, 0.1–0.5mV for MC). A phono preamp is required before line-level input. Same RCA connector as standard audio but different signal level.
| Pin | Name | Function | Type |
|---|---|---|---|
| L | Left RCA Center | Left RIAA phono signal (very low level) | ADC |
| R | Right RCA Center | Right RIAA phono signal | ADC |
| GND | Ground Lug | Turntable chassis ground (separate wire) | GND |