Thermionic Culture THE EARLYBIRD 4 4 Channel mic. Pre amp - Manual (Page 5)

©Thermionic Culture Ltd., July 2014 4
2 Controls
2.1 Gain
The gain is varied in steps of 5dB from 40dB to 60dB,
as stated on the front panel, though actual max gain is
2 – 4 dB more with 300 ohm input .impedance and a
low impedance source.
2.2 Bass filter
The response is flat when this switch is fully anti-clockwise.
It acts at 50 & 100Hz. The effect becomes more drastic as
the frequency drops.
2.3 Pad
Cuts down the input level by 20dB. Use with Z set to
1200Ω for cleanest results.
2.4 Z
Switches input impedance between 300Ω and 1200 Ω.
This is for matching microphones (see 4).
2.5 +48V
Applies phantom power to Mic In sockets. Switch on
only when an FET mic is used. NEVER use if inputs
may be unbalanced or with ribbon microphones..
2.6 Phase reverse
These switches will invert the phase of the signal.in
the corresponding channel, when in.
2.7 Output
trim
These controls are reverse linear attenuators,
operating after the electronics. The full output of the