This module is a volume controller and audio source selector that uses a relay and resistor network architecture, which completely eliminates the faults of mechanical potentiometers (contact resistance, friction noise, left/right imbalance) and significantly improves sound quality. The volume is adjusted in 1024 steps via a rotary encoder or remote control, with full MCU management ensuring stable variation without skipping or interference. The resistance value is 50 kΩ. The audio circuit is a purely resistive path, using high-precision audio resistors, Japanese NEC signal relays with silver contacts ensuring excellent conductivity, and ENIG (electroless nickel immersion gold) finished PCBs for the audio channels; the control board uses a HASL finish as the audio signal does not pass through it. The module offers 7 volume adjustment step amplitudes (1024-step mode corresponds to 4 LED flashes), allowing the fineness of adjustment to be adapted according to the gain of the power amplifier.  It incorporates numerous advanced features: source selection, instant mute, volume return to zero, progressive volume, programmable default volume at power-up, and protection against excessive volume, preventing the maximum level from being exceeded in order to protect the speakers. The power supply is dedicated exclusively to the control system and does not interfere with the audio path; depending on the configuration, the type of power supply may vary to ensure optimal stability without impacting sound quality. Adjustment procedures (default volume, maximum limit, no variation) are performed via a configuration button and clearly defined validation/return keys. 

 Control is via an ALPS 27 potentiometer. The volume controller comes with a source selection volume on which 4 pairs of RCA connectors (sold separately) can be installed. The power supply ground, as well as those of the left and right channels are independent. All functions can be controlled remotely using the supplied remote control.

How to use :

1. Method for setting the maximum volume limit: hold down the adjustment button (bottom left) until the adjustment indicator flashes continuously, then release. Next, adjust the volume to the desired level (for example, set to level 58). Once completed, regardless of how you operate the device, the volume will not exceed level 58 unless the setting is changed again. Then press the button at the top right to confirm; when the indicator light stops flashing, the setting is successful.

2. Default volume adjustment method: hold down the adjustment button (bottom left) until the indicator light flashes continuously, then release. Adjust the volume to the desired level, then press the central OK button at the top right to confirm; when the indicator light stops flashing, the adjustment is successful.

3. After entering adjustment mode, if you do not wish to make any adjustments, press the back button directly to exit adjustment mode.

4. Method for adjusting the 7 resistance step amplitudes: hold down the “adjust” button at the bottom left for a few seconds until the indicator light flashes continuously, release, press the ‘left’ button to observe the number of flashes, then press the “back” button directly.