Bose FREESPACE BMA-125 Service Manual page 14

Business music amplifier 120/230v
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Frequency
Output
(dB)
50Hz
1KHz
ref
20KHz
3.5 Adjust Input Five until 11.2Vrms is
measured across the 8Ω load. Reference a
dB meter to the output.
3.6 Measure the response according to the
following table.
Frquency
Output
(dB)
20Hz
1KHz
ref
20KHz
4. 25 Volt Output
Note: Place a jumper between the output
connector labeled "4Ω" and the output
connector labeled "PRI". Connect a 5Ω
load to the 25V output and the terminal
marked lo.
4.1 Apply a 120mVrms, 1KHz signal to
Input Five. Adjust Input Five to full output
at the 25V output (just before clipping).
4.2 Measure the output. It should be
25Vrms.
4.3 Measure the distortion. It should be
< .5%.
4.4 With the 25V output adjusted to
25Vrms, reference a dB meter to the
output. Measure the response according to
the following table.
Frequency
Output
(dB)
50Hz
1KHz
ref
20KHz
BMA-125 120V Test Procedures
Tolerence
(dB)
0
-2
-
0
-2.8
Tolerence
(dB)
0
-2
-
0
-2.5
Tolerence
(dB)
0
-2
-
0
-2.5
4.5 Adjust Input Five until 8.875 Vrms is
measured across the 8Ω load. Reference a
dB meter to the output.
4.6 Measure the response according to the
following table.
Frequency
Output
20Hz
1KHz
20KHz
5. 70 Volt Output
Note: Place a jumper between the output
connector labeled "4Ω" and the output
connector labeled "PRI". Connect a 40Ω
load to the 70V output and the terminal
marked lo.
5.1 Apply a 105mVrms, 1KHz signal to
Input Five. Adjust Input Five to full output at
the 70 Volt output (just before clipping).
5.2 Measure the output. It should be
70.7 Vrms.
5.3 Measure the distortion. It should be
< .5%.
5.4 With the output adjusted to 70.7Vrms,
reference a dB meter to the output. Mea-
sure the response according to the follow-
ing table.
Frequency
Output
50Hz
1KHz
20KHz
6. Tape Output
6.1 Apply a 100mV, 1KHz signal to Input
Five.
6.2 Adjust Input Five to the full clockwise
position.
14
Tolerence
(dB)
(dB)
0
-2
ref
-
-
-2.5
Tolerence
(dB)
(dB)
0
-2
ref
-
0
-2.5

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