Thermionic Culture THE EARLYBIRD 2.2 2 Channel mic, pre amp with eq - Manual (Page 10)

©Thermionic Culture Ltd., September 2010 9
5 Operational suggestions
5.1 Impedance
The Earlybird has a switchable input impedance for its
mic-amp inputs. This control has a large effect on the
tone obtained from whatever microphone is being
used. Technically 1200Ω is a good impedance for
Neumann FET mics whilst 300Ω is a good impedance
for ribbon mics such as the Coles 4038. However we
have found that the impedance control can be used as
a creative tonal adjustment.
Using a Neumann U87 with the 1200Ω setting the mic
will sound very open with an extended top end
presented to the listener. If the 300Ω setting is used
with the same mic, the gain will increase slightly but
the top frequencies will become slightly degraded and
lower in level. To the ear the sound seems to become
slightly more aggressive with a mid range punch to it.
This kind of thing can make all the difference when
recording things like vocals. For example a gentle
vocal will sound big and open on the 1200Ω setting,
whereas a rock vocal will punch through the mix when
using the 300Ω setting.
Ribbon mics may well come into their own when using
the Earlybird with the 300Ω setting. The gain, top
frequency response, noise and distortion will all be
optimum in this case and the ribbon mic can be used
in situations that were not possible before, or they may
simply sound better than before.
5.2 PAD
The PAD control on the Earlybird should be used
when very high levels are coming from the mic being
used. For example a valve mic that is near to a guitar
amp or drum kit will give out a high output level. Using