3. Instructions for the Power/Volume knob, GAIN and BASS switch

[Power/Volume Knob]
*Turn the Power/Volume knob clockwise until a click sound is heard to turn on the device; keep turning clockwise to increase the volume.
*Turn anticlockwise to decrease the volume; turn anticlockwise until a click sound is heard to turn off the device.

[GAIN switch]
H: Switch to high gain
L: Switch to low gain 
Choose the gain level based on the earphones you are using. It is suggested to adjust the volume knob between 9 and 3 o'clock. and choose the gain level for your own preference.

[BASS switch]
Bass boosting: Turn the BASS switch to ON to boost the bass performance. You could turn it on or off based on your personal preference.