HX-3, Headphone amplifier 3 out. The HX-3 is a portable, battery-powered headphone amplifier that has 3 outputs with separate volume controls. Balanced inputs on XLR and unbalanced on Tele TRS / 3.5mm TRS, as well as a loop through on Tele TRS. Powered by 2 AA batteries or external 5-18 VDC.† (Reduced price only applies to exhibition specimens)