BehringerMICROMIX MX400Ultra Low-Noise 4 Channel Line Mixer

Behringer MICROMIX MX400Ultra Low-Noise 4 Channel Line Mixer

Cable Matters 5-Pack 1/4 to 1/8 Headphone Adapter, 6.35mm to 3.5mm Adapter Male to Female, Gold Plated Stereo Headphone 3.5mm to 1/4 Adapter

Behringer MicroAMP HA400 4-channel Headphone Amplifier (HA400d1)