Manual
Table Of Contents
- Analogue Redbox User Handbook rev 1.92
- Contents
- Figures
- Warranty, Safety & Installation Information
- RB-MA1 Single & RB-MA2 Dual Microphone Amplifiers
- RB-SM1 Single & RB-SM2 Dual Stereo To Mono Converter
- RB-UL1 Single, RB-UL2 Dual & RB-UL4 Quad Stereo Unbalanced
- RB-LU4 Quad Stereo Balanced To Unbalanced Converter
- RB-BL2 Single & RB-BL4 Dual Bi-Directional Matching Converte
- RB-SL2 Twin Mono, or Stereo, Limiter
- RB-DA6 6 Way Stereo Distribution Amplifier
- RB-HD1 Stereo Headphone Amplifier
- RB-HD6 6 Way Stereo Headphone Distribution Amplifier
- RB-SD1 Silence Detection Unit
- RB-PMX4 10 Input, 4 Output Analogue Preset Mixer
- RB-LI2 Stereo Line Isolation Unit
- RB-PLI6 6 Way Mono Passive Line Isolation Unit
- RB-SS10 10 Way Stereo Analogue Source Selector/Mixer
- RB-LC3 3 Way Light/Power Controller
- Glossary
- Connectors And Cabling
- Index
Chapter 1 - RB-MA1 Single & RB-MA2 Dual Microphone Amplifiers
Redbox User Handbook 1-3
1.3.1. Mic Inputs
The XLR 3 pin sockets used for the microphone are electronically balanced. They have
the following connections:
Pin 1: Screen
Pin 2: Phase
Pin 3: Non-phase
1.3.2. Input Gain
Recessed pre-set potentiometers allow for adjustment of the gain of the microphone
inputs. This provides a gain range of 36dB to 75dB which enables the use of dynamic
and powered microphones. Connect the mic input and adjust the gain until the line
output is at the level that you need.
Fig 1-4: Switch to Control LF Filter and Phantom Power
1.3.3. Using Phantom Powered Microphones
For the input channel there are independent switches to provide phantom power at
+48V to the connected microphones. With phantom power selected, a voltage of
+48V is applied to pins 2 and 3 of the XLR connector to power the microphone,
supplied through 6k8 resistors giving a current of 14mA. Phantom power is used when
the switch is pointing towards the arrow.
1.3.4. Using the LF Filter
A switch also provides control for a high pass filter with low frequency roll off at
125Hz. The roll-off filter is in when the switch is in the down position (towards the
arrow).
1.3.5. Output
The XLR 3 pin plug output connector is electronically balanced and can be wired
unbalanced by grounding the non-phase signal, allowing you to feed balanced and
unbalanced equipment. It has the following connections:
Pin 1: Screen
Pin 2: Phase
Pin 3: Non-phase
The connector provides a line level output with an impedance of <50Ω and a
maximum output level of +28dBu.
1
On On
On On
234
1. Channel 1 Low Frequency (L.F.) Filter
2. Channel 1 Phantom Power
3. Channel 2 Phantom Power (only applies to MA2)
4. Channel 2 Low Frequency (L.F.) Filter (only applies to MA2)