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3. Channel 1 and 2 Mic Input Signal to
Noise Ratio (Dynamic Range) Tests
3.1 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.
3.2 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.
3.3 Using a balanced XLR male input cable,
apply a 1 kHz, -30dBV signal to the channel
1 input.
3.4 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.
3.5 Move the shorting plug from the Amp 2
IN jack to the Amp 1 IN jack and repeat
steps 3.1 to 3.4 for the channel 2 Mic input.
4. Channel 1 and 2 Line Input Gain Tests
4.1 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.
4.2 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.
4.3 Using an unbalanced 1/4" phono jack
input cable, apply a 1 kHz, -10dBV signal to
the channel 1 input.
TEST PROCEDURES
28
4.4 Reference a dB meter to the input level.
Measure the gain output at the Amp 1 OUT
jack. It should be +28.5 dB + 4dB.
4.5 Move the shorting plug from the Amp 2
IN jack to the Amp 1 IN jack and repeat
steps 4.1 to 4.4 for the channel 2 Line input.
5. Channel 1 and 2 Line Input Frequency
Reponse and Distortion Tests
5.1 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.
5.2 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.
5.3 Using an unbalanced 1/4" phono jack
input cable, apply a 1 kHz, -10dBV signal to
the channel 1 input.
5.4 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.
5.5 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.
5.6 Move the shorting plug from the Amp 2
IN jack to the Amp 1 IN jack and repeat
steps 2.1 to 2.5 for the channel 2 Line input.
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