The PA4 mixer features input gain and high bass adjustment, a built-in 48V phantom power supply for condenser microphone direct power supply, a high-definition headset output port, MP3 broadcast, and the ability to connect a computer with a sound card directly to a PC. The mixer is small and thin, and it can be powered directly from a computer's USB port. It requires no extra power and can be connected to a computer via USB. If you don't have access to an external converter, you can use handheld power or USB AC/DC. The transformer is the source of control for the adapter.   The mixer is a multi-purpose 4-channel Power mixer with a sound card that can be used for home music production, webcasting, K song production, and other applications. FEATURES2 channel signal  input and one channel stereo inputOne main channel output, one AUX output and feedback. Independent channel for recording output and monitor. Low-noise, a high-precision microphone preamplifier with perfect sound quality. Balanced XLR microphone input and balanced TRS line inputs, 3-band channel EQ.48V DC phantom power will responsible for connecting with the condenser mic. and power  supply for the input port.   Port for earphone monitor  Precision logarithmic double 10 LED level display  MP3 module, USB interface  The built-in switching power supply is flexible (AC100-240V AC), with low power consumption.