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Loud-ESP32, Loud-Esparagus and Esparagus Echo

The Sonocotta Loud-ESP32 boards drive MAX98357A I2S amplifiers directly — no DAC in front, no I2C control port. Speakers connect straight to the board.

A MAX98357A has exactly one control line: an active-high SD_MODE enable. The firmware registers a minimal DAC driver whose only job is to drive that pin from RTSP playback events, so the amplifier is held muted until a client actually presses play and drops back to standby on pause. That is the same power-state handling the Esparagus Audio Brick does over I2C, reduced to one GPIO.

Variants

Environment Chip Amps Ethernet Display Bluetooth Prebuilt
loud-esp32 ESP32 1 yes SH1106 OLED — —
loud-esp32-bt ESP32 1 yes SH1106 OLED yes yes
loud-esparagus ESP32 2 — — — —
loud-esparagus-bt ESP32 2 — — yes yes
loud-esp32-s3 ESP32-S3 2 yes SH1106 OLED — yes
esparagus-echo ESP32-S3 2 yes — — yes

Both amplifiers share the one enable pin, so a dual-amp board mutes and unmutes as a unit. Bluetooth Classic exists only on the original ESP32, so neither S3 board has a -bt build; on an ESP32 the published binary is the Bluetooth one.

Esparagus Echo is the same amplifier arrangement on the Echo's S3 board — Ethernet, an RGB status LED and no display header.

Features

  • One or two MAX98357A Class-D amplifiers, speakers connected directly
  • Amplifier held muted until playback starts, standby on pause, off on disconnect
  • Software volume control — the MAX98357A has no volume register
  • 8 MB flash
  • Bluetooth A2DP on the ESP32 variants
  • W5500 SPI Ethernet with automatic WiFi failover, except on Loud-Esparagus
  • SH1106 OLED over SPI, sharing the Ethernet bus, on Loud-ESP32 and Loud-ESP32-S3

Flashing

Use the Loud or Esparagus Echo installer on the flashing page.

# ESP32 — AirPlay + Bluetooth + Ethernet + OLED
pio run -e loud-esp32-bt -t upload
pio run -e loud-esp32-bt -t uploadfs

# ESP32 — Esparagus variant, dual amp over WiFi
pio run -e loud-esparagus-bt -t upload
pio run -e loud-esparagus-bt -t uploadfs

# ESP32-S3 — dual amp, Ethernet + OLED
pio run -e loud-esp32-s3 -t upload
pio run -e loud-esp32-s3 -t uploadfs

# ESP32-S3 — Esparagus Echo
pio run -e esparagus-echo -t upload
pio run -e esparagus-echo -t uploadfs

idf.py set-target esp32
idf.py -DSDKCONFIG_DEFAULTS="config/sdkconfig.defaults;config/sdkconfig.defaults.loud-esp32;config/sdkconfig.defaults.bt" build
idf.py -p /dev/ttyUSB0 flash

Swap in config/sdkconfig.defaults.loud-esp32-s3 or config/sdkconfig.defaults.esparagus-echo after idf.py set-target esp32s3 for the S3 boards.

Default GPIO assignments

Function Loud-ESP32 Loud-Esparagus Loud-ESP32-S3 Esparagus Echo
I2S BCK 26 26 14 18
I2S WS 25 25 15 8
I2S DO 22 22 16 17
Amp enable (SD_MODE) 13 13 17 9
Status LED — 33 — 42
SPI SCLK 18 — 12 12
SPI MOSI 23 — 11 11
SPI MISO 19 — 13 13
Ethernet CS 5 — 10 10
Ethernet INT 35 — 6 6
Ethernet RST 14 — 5 5
Display CS 15 — 39 —
Display DC 4 — 40 —
Display RST 32 — 38 —

The Loud-ESP32-S3 enable pin moved

CONFIG_DAC_ENABLE_GPIO is GPIO 17 for rev G and later hardware. Rev F used GPIO 8. On a rev F board, override it in a custom configuration or nothing will ever unmute.