Bose AmPlus 50 Supplement Manual page 30

4. Distortion Test
4.1 Set up the AmPlus™ Amplifier as listed
in the Test Setup Notes.
4.2 Install the Model 1B Equalizer PCB into
the EQ jack for the channel you are using
for this test, J9 for channel 1 or J10 for
channel 2.
4.3 Shut off the AmPlus Amplifier, and
place switch S1 on the Model 1B Equalizer
PCB to the SURFACE position.
4.4 Apply a balanced 130 mVrms, 1 kHz
signal to the inputs at J1.
4.5 Measure the distortion level at the
output at J6. It should measure ≤ 0.2%
THD.
5. Noise Test
5.1 Set up the AmPlus Amplifier as listed in
the Test Setup Notes.
5.2 Short the inputs of the AmPlus Amplifier
to ground.
5.3 Install the Model 1B Equalizer PCB into
the EQ jack for the channel you are using
for this test, J9 for channel 1 or J10 for
channel 2.
5.4 Using a 30 kHz low pass filter, measure
the noise level at the AmPlus Amplifier
output at J6.
5.5 It should measure < -45.0 dBV.
6. DC Offset Test
6.1 Set up the AmPlus Amplifier as listed in
the Test Setup Notes.
6.2 Short the inputs of the AmPlus
Amplifier to ground.
TEST PROCEDURES
30
6.3 Install the Model 1B Equalizer PCB
into the EQ jack for the channel you are
using for this test, J9 for channel 1 or J10
for channel 2.
6.4 Measure the DC Offset level at the
Model 1B Equalizer PCB at J1 pin 5 and
at TP 21. TP 21 is located on the etch side
of the PCB, at switch S1, toward the center
of the board.
6.5 The DC Offset level should be
< 10 mVdc.
Model 8 Equalizer PCB Response Tests
1.1 Set up the AmPlus Amplifier as listed in
the Test Setup Notes.
1.2 Apply a 31.5 mVrms, 1 kHz signal to
the AmPlus Amplifier inputs at J1.
1.3 Reference a dB meter to the output
level at J6. This is the reference level for
this test.
1.4 Shut off the AmPlus Amplifier and
install the Model 8 Equalizer PCB into the
EQ jack for the channel you are using for
this test, J9 for channel 1 or J10 for chan-
nel 2.
1.5 Turn on the AmPlus Amplifier and
measure the gain. There should be a
-3.5 dB ±1.0 dB change in gain at the
output.
1.6 Reference a dB meter to the output
level at J6.
1.7 Perform the tests as listed in Table 13,
Model 8 Full Range Response Tests.