14
GENERAL
The LAKE PEOPLE MIC-AMP F355 is an
extremely low-noise and fully featured micro-
phone preamplifier with excellent specifica-
tions.
Due to its versatile concept and high level
capability it is also suitable for line signal
boosting and balancing.
The gain element of the standard version is a
high quality instrumentation amplifier. As an
option, MIC-AMP F355 may be equipped with
a sophisticated Class-A frontend, built with
discret components.
Gain is controlled with two knobs per channel:
a twelve-step rotary switch sets coarse gain in
6-dB steps from 0 to +66 dB. A center-
detented potentiometer allows fine adjustment
within a range of +/- 5 dB.
The lo-cut filter may be set individually from 10
to 250 Hz.
Each channel is equipped with buttons for
- Phantom powering
- Pad
- Phase reverse
- (de-) activation of Gain-Fine adjust
- (de-) activation of Lo-Cut control
- Mute
The state of all these buttons is reported by
LEDs.
In order to keep the signal path as pure as
possible, the electronic components of the
Gain-Fine control and the Lo-Cut filter stage
may be removed completely with the aid of
relais.
Whilst switching on or off the phantom power,
the outputs may be muted during 4 seconds.
A sixteen-segment LED bargraph with semi-
logarithmical law displays the output level over
a range of 36 dB. Display sensitivity can be
adjusted to the user's requirements with a trim
located on the front panel.
A clip LED starts flashing at levels above +20
dBu and thus reliably warns against distortion.
The electronically balanced inputs and outputs
are situated on the rear panel.
Each channel is equipped with two outputs.
OPTIONS
(see page 19 for more details)
Each channel may be equipped with a Class-A
input stage.
Each output can be equipped with transformer
balanced outputs consisting of active feedback
transformers.
Each channel may be equipped with a versatile
GP-I/O interface.
THE CASE
The grounded case is made of 1 -2 mm thick
stainless steel. This provides high mechanical
stability and resistance against rough handling.
The cases surfaces are not treated with any
material, so providing excellent electrical con-
ductances for optimum EMC characteristics.
THE POWER SUPPLY
Mains is connected via a built-in IEC-CEE
mains socket. If necessary, mains voltage can
be internally altered from 230 to 115 V.
The "POWER"-switch is situated on the front
panel. Power status is displayed by a LED
situated below the power switch.
An oversized toroidal transformer delivers the
internal supply voltages.
These are:
- +24 V unregulated for LED´s and relais
- +/-18 V linear stabilized for the analog
circuitry
- +5 V linear stabilized for the processors
- +48 V via DC/DC converter for phantom
powering
THE MAINS FUSE
The 0,25 AT fuse is internally soldered in place
on the power supply PCB.
ATTENTION !!
FOLLOW THE SAFETY INSTRUCTIONS:
A blown fuse may refer to internal problems
and should only been replaced during qualified
servicing works !!
