17
3.
Enter the ADC Sensitivity Setup menu by powering up the m802 while the PEAK button is pressed.
4.
Move the encoder until “ADC Sensitivity” is highlighted. Click the encoder to edit the parameter. Ro-
tate the encoder to choose the sensitivity setting you wish to modify ((A) or (B)). Click the encoder
once the desired setting is selected.
5.
Now rotate the encoder to the right column until it highlights the Sensitivity CAL setting correspond-
ing to setting ((A) or (B)) you just selected.
6.
Click the encoder and rotate it to choose between the four available sensitivities. Once selected, click
the encoder again to disengage the parameter edit mode.
7.
Rotate the encoder until “DONE” is highlighted. Click the encoder and the preamp will reboot.
8.
Verify that the A/D converter is turned on.
The procedure in this section configures the m802 hardware. The following steps should be repeated for
each channel:
1.
Set the preamp gains to 16.4dB.
2.
Connect a signal generator to the channel input and connect a level meter that reads dBu to the
output of the channel.
3.
Increase the generator level until the level until the preamp output is +4dBu.
4.
Using a non conductive tweaker tool, adjust the trim control corresponding to the current channel
and sensitivity range (A) or (B). Each channel is labeled on the A/D converter analog input card (
see
figure 7 below
). Trim (A) and trim (B) are also labeled. While adjusting the trim control, monitor
the digital output on your recording device. Turn the trim until the digital level matches the desired
headroom level. That is the level you will be adjusting to will be the desired headroom in decibels be-
low full scale. For example if you have se20dBu = 0dBFS (16dB Headroom) for sensitivity (A),
turn the trim (A) potentiometer until your digital meters read -16dBFS. If you have se24dBu
= 0dBFS (20dB Headroom) for sensitivity (B), turn the trim (B) potentiometer until your digital meters
read -20dBFS.
5.
Once all channels have been recalibrated, shut down the m802 and reinstall the top cover.
figure 7 / a/D trim locations
