This item is unopened! It's been in storage for a few years and now I'm trying to free up some space because I know I'll never use them.

I have two of these units, the same exact condition, both unopened and never used.

Description from the ART website:

The HeadAmp 4 is a high-output, low-noise, low-distortion headphone amplifier that extends the connectivity of your mixer, audio interface, or other sound source.

It features four output channels with independent volume controls. Each output has 1/4 and 1/8 stereo connections that can be used simultaneously, so you can connect up to 8 pairs of headphones.

Compact and durable, the HeadAmp 4 is an ideal solution to split a signal between multiple listeners.

Need more outputs and control? Check out the HeadAmp 6 and HeadAmp 6 Pro.

Features

• 4x Output Channels
• Independent Volume Per Channel
• Stereo 1/4" and 1/8" Inputs
• 2x 1/4" and 1/8" Headphone Outputs per Channel
• Supports up to 8 Pairs of Headphones
• 12V DC Adapter Included

Inputs1/4" & 1/8"Outputs1/4" & 1/8"

Input Impedance90.9k Ω

Output Impedance47 Ω (Each Output)

Maximum Input Level+14 dBV

Maximum Output Level+14 dBu

Maximum Gain20 dB

Frequency Response20 – 20 kHz

Total Harmonic Distortion<0.01%

Signal to Noise Ratio> 90dB (ref 0 dBu)

Power Requirements12 V DC

Dimensions (LWH)4.1″ x 4.6″x 1.85″, 104 cm x 117 cm x 47cm

Weight1.3 lbs (0.61kg)