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Usage and menu system
The amplifier's user interface is controlled by a 16x02 LCD and four push-button switches: OPT (Action), UP (+), DOWN (-), and MUTE.
When the amplifier is powered on and no buttons have been pressed for a few seconds, it enters the idle state, which displays a spectrum analyzer on the 16x02 LCD.
| Button | Action | Function |
|---|---|---|
| UP (+) | Single Press | Increases the master Volume level. |
| DOWN (-) | Single Press | Decreases the master Volume level. |
| MUTE | Single Press | Toggles Mute ON/OFF. When ON, the display shows "MUTE". Pressing UP or DOWN while muted will also un-mute the audio. |
| OPT (Action) | Single Press | Enters the Settings Menu. |
Pressing the OPT (Action) button from the main screen enters the Settings Menu, which allows for configuration of the audio processor.
| Button | Function in Menu |
|---|---|
| OPT (Action) | Cycles through the menu items in order: Input Channel → Bass Level → Treble Level → Channel Mode → Output Mode → Exit. |
| UP (+) | Increases the value or cycles to the Next option for the currently displayed menu item. |
| DOWN (-) | Decreases the value or cycles to the Previous option for the currently displayed menu item. |
| MUTE | Toggles Mute ON/OFF. |
Use the UP and DOWN buttons to change the setting displayed on the LCD.
| Menu Item | Function | UP Action | DOWN Action | Displayed Options/Range |
|---|---|---|---|---|
| Input Channel | Selects the active audio source input. | Cycle to next source. | Cycle to previous source. | BT L+R, Line L+R, BT L, BT R, Line L, Line R |
| Bass Level | Adjusts the Bass tone level. | Increases level. | Decreases level. | Numeric value (relative to 0dB) |
| Treble Level | Adjusts the Treble tone level. | Increases level. | Decreases level. | Numeric value (relative to 0dB) |
| Channel Mode | Selects the stereo processing mode. | Cycle to next mode. | Cycle to previous mode. | Spatial, Stereo, Pseudo, Mono |
| Output Mode | Toggles the hardware audio output path. | Toggles the output. | Toggles the output. | Speaker, HPhone (Headphone) |
| Exit | Saves all changes to the amplifier's memory (EEPROM) and returns to the main screen. | Saves and exits. | Saves and exits. |
There are two ways to exit the settings menu and apply changes:
- Select Exit: Press OPT to navigate to "Exit," then press either UP or DOWN.
- Idle Timeout: The menu will automatically save all settings and exit if there is no button activity for a certain period of time.
The JP3 and JP4 jumpers are 3-pin headers used to select the gain level for the YDA138 digital power amplifier chip. By physically placing a jumper cap in one of the two possible positions on each 3-pin header, the user can switch between a low gain setting and a high gain setting. Selecting a lower gain is generally preferred for higher-input signal sources to prevent clipping or distortion, while selecting a higher gain is necessary for lower-input sources (like some older media players) to achieve maximum volume and drive the speakers effectively.
| JP3 | JP4 | Gain Level (dB) |
|---|---|---|
| Low | Low | 18 dB |
| Low | High | 24 dB |
| High | Low | 30 dB |
| High | High | 36 dB |