Headphone output levels shall be independently controllable by user. Maximum output power to each headphone channel shall be 1 watt stereo. A rotary knob on the front panel of the headphone amplifier shall control the headphone amplifier's master output level to each of the six headphone jacks.

Input signal levels shall be controlled by the user by adjusting the output level of the device feeding the headphone amplifier. An LED indicator on the front panel of the headphone amplifier shall be employed to indicate when the input signal level is within 2 dB of actual clipping.

Upon power-up, the headphone amplifier shall incrementally increase output levels from zero to the level specified by each output control over a period of 750 milliseconds in order to minimize hearing damage caused by high level audio transients or excessively high level settings from a prior user.

The headphone amplifier inputs shall be electronically balanced capable of accepting balanced or unbalanced line level audio program. Inputs shall be presented as dual 1/4" TRS jacks for balanced left and right input audio, and a single 1/4" TRS jack for unbalanced stereo input. The unbalanced stereo input shall be available on both the front and the rear panels. The 1/4" TRS unbalanced stereo jack on the front panel shall be available for use as a loop-through input or an auxiliary output. The unit's balanced audio inputs shall have an impedance of 20 k ohms.

A frequency response of 20 Hz to 20 kHz shall be delivered by the headphone amplifier.

Total harmonic distortion shall not exceed 0.04% @ 300 ohms.

A front-panel rocker-type power switch shall provide visual indication with red marking. The power supply shall be internal with a thermally-fused transformer mounted in a low hum orientation. The transformer and primary side of the power supply shall be isolated from the secondary and electronics by means of a steel hum isolation shield. The power cord shall be detachable from an international standard IEC 320 power inlet receptacle. The unit shall be constructed to meet or exceed all applicable international safety and regulatory agencies' standards. The unit shall be powered from 120 VAC 60 Hz) or 100 VAC, 50/60 Hz, 230 VAC 50 Hz, 240 VAC 50 Hz). Unit housing shall be of all steel construction and shall be rackmountable in an IEC standard 19" rack and shall occupy a 1U (1.75") rack space. The unit's nominal power consumption shall be 20 Watts.

The unit shall be a DOD SR460H headphone amplifier.