Manual

38
Redbox User Handbook No 2
11 RB-HD1 Stereo Headphone Amplier &
RB-HD2 Dual Headphone Amplier
Introduction
Fig 11-1: RB-HD1 Front Panel.
The RB-HD1 is a 1U rack-mount stereo headphone amplier for driving up to two pairs of
professional stereo headphones from a single stereo or mono input. One headphone socket
is on the front panel with one on the rear.
The main stereo input uses electronically balanced XLR-3 connectors on the rear panel,
which can be wired un-balanced. The output volume for the headphones can be controlled
either by a pot situated on the front panel or a VCA signal supplied externally via the remote
connector.
A mono input can be mixed into the main headphone feed, for example, for mixing in
talkback to the headphones. This has an input level control via a recessed adjustable
potentiometer. The mono mix input can also be controlled remotely.
A stereo/mono switch is recessed on the rear panel to prevent accidental knocking. With
mono selected, audio is sent to both left and right ear pieces. A LED power indicator on the
front panel displays the power supply connection.
Fig 11-2: RB-HD2 Front Panel.
The RB-HD2 is a high performance 2-way stereo headphone distribution amplier for
driving up to 2 pairs of professional stereo headphones from a single stereo or mono input.
A switch on the rear panel enables the distribution of a mono signal to all four outputs (i.e.
both earpieces of a pair of stereo headphones) via the left channel input. The stereo/mono
switch is located on the rear panel to prevent accidental knocking.
The XLR-3 inputs are electronically balanced and can be wired unbalanced. There are two
pre-set controls on the rear panel that adjust the level of the master input signal to the
outputs.
Each output is on a ¼” stereo jack socket and is designed to drive 150mW into 32 ohm to
600 ohm stereo headphones. The outputs are individually buered with their own front
panel volume control. A LED power indicator on the front panel displays the power supply
connection.
HEADPHONE DISTRIBUTION AMPLIFIERS-RB-HD1 & RB-HD2
HEADPHONE DISTRIBUTION
AMPLIFIERS
11