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6. Channel 1 and 2 Line Input Signal to
Noise Ratio (Dynamic Range) Tests
6.1 Place a 1/4" mono shorting plug into the
Amp 2 IN and Amp 3 IN jacks on the right
hand side of the input/output panel. This will
disable the channel 2 and 3 amplifiers while
testing the channel 1 amplifier.
6.2 On the left hand side of the input/output
panel, set the channel 1 Mic Trim control to
the 6 setting. Ensure that the Line In +20dB
gain and the Phantom Power push buttons
are not pushed in.
6.3 Using an unbalanced 1/4" phono jack
input cable, apply a 1 kHz, -10dBV signal to
the channel 1 input.
6.4 Reference a dB meter to the output level
at the Amp 1 OUT jack. Remove the input
signal and measure the A-Weighted output
level. It should be -80dB minimum.
6.5 Move the shorting plug from the Amp 2
IN jack to the Amp 1 IN jack and repeat
steps 6.1 to 6.4 for the channel 2 Line input.
7. Channel 3 and 4 Line Input Gain Tests
7.1 Place a 1/4" mono shorting plug into the
Amp 1 IN and Amp 2 IN jacks on the right
hand side of the input/output panel. This will
disable the channel 1 and 2 amplifiers while
testing the channel 3 amplifier.
7.2 On the left hand side of the input/output
panel, set the channel 3 Level control to the
6 setting.
7.3 Using an unbalanced 1/4" phono jack
input cable, apply a 1 kHz, -20dBV signal to
the channel 1 input.
7.4 Reference a dB meter to the input level.
Measure the gain output at the Bass/Amp 3
OUT jack. It should be +40.1dB + 3dB.
7.5 Repeat steps 7.1 to 7.4 for the channel 4
Line input.
TEST PROCEDURES
29
8. Channel 3 and 4 Line Input Frequency
Reponse and Distortion Tests
8.1 Place a 1/4" mono shorting plug into the
Amp 1 IN and Amp 2 IN jacks on the right
hand side of the input/output panel. This will
disable the channel 1 and 2 amplifiers while
testing the channel 3 amplifier.
8.2 On the left hand side of the input/output
panel, set the channel 4 Mic Trim control to
the 6 setting.
8.3 Using an unbalanced 1/4" phono jack
input cable, apply a 1 kHz, -20dBV signal to
the channel 1 input.
8.4 Use an 80kHz low-pass filter on your
measuring equipment. Reference a dB
meter to the input level. Measure the fre-
quency response at the Amp 1 OUT jack.
It should be 0dB + 3dB from 30Hz to 15kHz.
8.5 Measure the Total Harmonic Distortion
(THD) level at the Amp 1 OUT jack. It should
be 0.25% max at 1kHz and 1.5% max at
15kHz.
8.6 Repeat steps 8.1 to 8.5 for the channel
4 Line input.
9. Channel 3 and 4 Line Input Signal to
Noise Ratio (Dynamic Range) Tests
9.1 Place a 1/4" mono shorting plug into the
Amp 1 IN and Amp 2 IN jacks on the right
hand side of the input/output panel. This will
disable the channel 1 and 2 amplifiers while
testing the channel 3 amplifier.
9.2 On the left hand side of the input/output
panel, set the channel 3 Level control to the
6 setting.
9.3 Using an unbalanced 1/4" phono jack
input cable, apply a 1 kHz, -10dBV signal to
the channel 1 input.
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