Pioneer Dj DDJ-FLX4 Portable 2-Channel rekordbox DJ and Serato Controller (Graphite) - Manual (Page 38)

Connections
38
En
• When using the unit with a USB power adapter or mobile battery
connected to the USB port (for power supply), make sure it has a
maximum voltage of 24V or less and DC 9V 3A.
Use a USB cable certified to the appropriate standard.
Use a mobile battery without a power-saving function.
• The [MIC] input terminal only supports an unbalanced input.
When not using the microphone, turn the [MIC LEVEL] knob to the
minimum level.