The MA400 features XLR Thru jacks and provides superb noise-free operation. Just connect your mic to the Mic Input and send a line from the Mic Thru to your main mixer. You can even use studio-grade condenser mics, as the MA400 will pass +48 V phantom power, if your mixer is so equipped. The Phones jacks accept both 1/4" and 1/8" headphone and earbud connections, making the MA400 ideal for hardwired IEM (in-ear-monitor) applications, such as singing drummers and keyboardists. The MA400 comes with a dedicated 12V DC power supply and an LED to indicate when it is powered up.