the Samson QH4 proves you don't have to spend an arm and a leg to get one. This extremely utilitarian 4-channel headphone distribution amplifier offers many of the same features Balanced inputs ensure low noise and distortion, while 1/8" stereo aux I/O lets you daisy-chain multiple QH4s together. Mono summing also makes this headphone amp perfect for single-ear monitoring and checking phase cancellation when you mix, and there's a master mute switch to save your ears when you need to make connection changes on the channel you're monitoring.

4-channel Headphone Distribution Amplifier with Balanced Inputs, Channel Volume Controls, Master Mono Summing and Mute Control, and Aux I/O for Daisy Chaining

Type:Headphone Amp
Input Channels:Stereo/Mono channel in
Output Channels:4 stereo channels (mono switchable)
Analog Inputs:2 x 1/4" (left, right), 1 x 1/8" (aux in)
Analog Outputs:1 x 1/8" (aux out)
Headphones:4 x 1/4" TRS
Controls per Channel:Volume
Form Factor:Desktop
Power Supply:15V DC power supply (included)
Height:2.7"
Width:6.25"
Depth:11.5"

Samson QH4 4-channel Headphone Amplifier