Ceiling Microphone Preamp

Microphone Preamp

For normal use, just turn on the power switch and it should be functioning fine. If you need to change any settings CHANGE THEM BACK AFTER. Below numbers correspond to the nobs on the preamp. 

1. Phantom Power
   1. Applies 48V Phantom Power to the attached microphone. Should be on. 
2. Polarity
   1. Reverses the polarity of the input signal. 
3. Mic Gain
   1. Switched gain control ranging from 10 to 60dB in constant 10dB steps. This will affect the volume. 
4. Input Level
   1. Meter 12-segment LED meter measuring the analogue output level, relative to 0dBFS, where 0dBFS= +18dBu. This matches the Black ADC unit. 0dBFS (FS stands for Full Scale) is the maximum level that can be represented by the digital signal. The ‘OVER’ indicator will illuminate at +1dBFS. Note that this does not indicate the analogue clip point, which is 3-4dB higher.
5. Line Selector
   1. Selects the line input. Should be off
6. Line Gain
   1. Not used
7. Gain Trim
   1. Continuous fine-adjustment of input gain from 0 to 10dB. 
8. High-Pass Filter
   1. A 12dB/Octave filter, variable from 30 to 225Hz. Great for eliminating microphone stand rumble, air conditioning noise, or thundering bass from the room next door.
9. High-Pass Filter In
   1. Switches the filter in and out of circuit, allowing you to hear its impact.
10. HMX
    1. Probably not needed.
11. HMX In
    1. Should be off
12. Inst/DI Input
    1. Can plug in another device, it will override the other inputs. The DI input’s gain can then be controlled by either the mic or line gain controls, whichever is selected. This lets you choose the gain range and step size that best suits your chosen instrument.

For more information, refer to the manual.