Audio¶
| Board | Audio |
|---|---|
| K8-Pro, K8-Max, K16-Pro, K16-Max, K32-Pro, K32-Max | Built-in stereo DAC, 3.5 mm line out, FM transmitter socket |
| K64D-B, K128D-B, K16A-B, K32A-B | Built-in stereo DAC, 3.5 mm line out, FM transmitter socket |
| K16, K32, K8-PB, K4-PB, K40D-PB, PocketScroller v2, v3 and -16, K8-B, K8-B-Scroller, OctoPlus | None built in. Use a USB sound card. |
| K8-Pi, K2-Pi-Servo | The Pi 3 B+ or Pi 4's own audio jack (the Pi 5 has none), or a USB sound card. |
| K2-Pi0 | None (the Pi Zero has no audio output). Use a USB sound card on the Pi's USB port. |
| PiOLED 3.0 With Audio | Built-in PCM5122 stereo DAC, 3.5 mm line out. See Pi-OLED. |
Line output¶
The built-in audio uses a PCM5102A 24-bit DAC on the board, so it has no USB jitter or ground noise.
- 3.5 mm stereo jack (tip = left, ring = right, sleeve = ground).
- Line level (about 2 V RMS at full volume). It's meant for an amplifier, powered speakers or an FM transmitter's line input. It is not a headphone amplifier, though headphones will work at low volume.
- FPP lists it as the CapeAudio sound card and selects it automatically. Volume is set in FPP's status page or with the volume commands. See the FPP manual.
FM transmitter socket¶
Boards with built-in audio also have an 11-pin socket marked
RST SCL SDA 3.3V G L R for the plug-in
Si4713 FM transmitter. The module receives
the same audio as the line output, and FPP's FM transmitter plugin controls it over I²C.
| Pin | Signal |
|---|---|
| 1 | RST (module reset) |
| 3 | SCL |
| 4 | SDA |
| 7 | 3.3 V |
| 8 | GND |
| 10 | Left audio |
| 11 | Right audio |
| 2, 5, 6, 9 | not connected |
Warning
Broadcasting on FM is regulated. Check the power and frequency rules where you live.
USB sound cards¶
On boards without built-in audio, plug a USB sound card into a USB-A port and select it in FPP under Settings → Audio/Video.