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PRE-01 front panel.
The microphone preamplifier PRE-01 has been designed to match Audiomatica’s microphones
MIC-01, MIC-02 and MIC-03. It is particularly useful when the microphone has to be operated far
from the analyzer or when weighted measurements are needed. PRE-01 powers the microphone
connected to its input with an 8.2V phantom supply and adds a selectable weighting filter (A or B
or C); also available there is a 20 dB gain stage. The unit is
operated with one standard 9V battery
or with an external DC power supply.
FREQUENCY RESPONSE: 7Hz
WEIGHTING FILTERS: A, B, C (IEC 651 - TYPE I)
PHANTOM POWER SUPPLY: 8.2V (5600 Ohm)
GAIN : 0 & 20dB (INTERNAL SETTINGS)
INPUT IMPEDANCE: 5600 Ohm
OUTPUT IMPEDANCE: 100 Ohm
MAXIMUM OUTPUT VOLTAGE (@1kHz): 25 Vpp
THD (@1kHz): 0.01%
INPUT NOISE (@20dB gain): 7uV LIN, 5.3uV A
>12h (alkaline cell)
USE OF THE PREAMPLIFIER
The MIC-01, MIC-02 or MIC-03 microphone cable has to be connected to the preamplifier input
while the preamplifier output has to be connected to the analyzer input. The unit is switched on
with the POWER switch, while the TEST push-button controls the state of the unit; when pressing
it, if the led light is on then the unit operates correctly, otherwise not: either the battery is low or
the external power supply is not connected. The FILTER switch inserts the weigthing filter. To
choose the desired weighting filter type and to set the amplifier gain you have to modify the
preamplifier settings as described later.
NOTE: if the 20 dB gain stage is inserted the overall sensitivity (microphone + pre) is 10
times higher. For example if your microphone has a sensitivity of 17.1 mV/Pa and you
preamplify it of 20 dB then you get a sensitivity of 171 mV/Pa.
ELECTRICAL & ACOUSTICAL TESTS
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USE OF AN EXTERNAL POWER SUPPLY
As it may be seen from the above figure the unit can be powered by an external DC power supply
in the range 9÷16V capable of delivering a minimum of 100 mA. The silk-screen also reports
connector wiring with the positive at the tip contact.
HOW TO REPLACE THE BATTERY
Open the battery holder and substitute the 9V cell with an equivalent among the many available in
the market (PP3, 6AM6, 6LR6, MN1604 etc.). You may also use a rechargeable one. Take great
care to the polarity when inserting it into the holder.
TO SELECT A WEIGTHING FILTER
Use dip switches 1-3, selecting one at a time, as follow:
- ‘A weighting’ filter
dip switch 1 ON (2&3 OFF)
- ‘B weighting’ filter
dip switch 2 ON (1&3 OFF)
- ‘C weighting’ filter
dip switch 3 ON (1&2 OFF)
Factory setting: ‘A weighting’ filter.
TO CHANGE AMPLIFIER GAIN
Use dip switch 4 as follow:
- +20 dB gain
dip switch 4 ON
- 0 dB gain
dip switch 4 OFF
Factory setting: +20 dB gain.
PRE-01 rear panel.
- MICROPHONE PREAMPLIFIER
MADE IN ITALY - AUDIOMATICA SRL
1 2 3 4
ELECTRICAL & ACOUSTICAL TESTS
2 (C) 2007 AUDIOMATICA