© 2010 Wohler Technologies, Inc. All rights reserved.
18
AMP V Series User Guide
Line Level Calibration Instructions
Line Level (Auto) Meter Calibration
The unit is calibrated at the factory prior to shipping for +4 dBU = -20
dBFS = 0dB on the meter. To recalibrate:
1.
Turn on the power.
2.
Apply the desired reference level (nominal 0) signal to all
channels.
3.
Make sure the Reference Level DIP sections (2 and 3) are set to the
nearest level of the input signal being applied for calibration (i.e.,
0, +4, +6 or +8). The user should make sure that the signal applied
to all four channels is /- 4 dB of the reference level
selected by DIP switch sections 2 and 3.
4.
Place DIP section 1 in the down position.
5.
Wait 10 seconds. The unit will remove the previous calibration and
the new calibration will be applied.
Note:
Position 6 of the DIP Switch is not used.
Note:
For more accurate indication of signal levels, meters are
tuned to effect a “rounding” function, which occurs between
the thresholds of any two bar graph segments. This means
the level meter zero (0) LED sigment will turn on at one-half
the smallest spacing between LED segments (mid-scale
resolution) before that segment’s scale indication.
Table 1–2
Meter Segment Rounding Offsets
Scale
26-Segment Bar
Graphs
53-Segment Bar
Graphs
Analog, Extended VU
.5 dB
.5 dB
Digital
Nordic
DIN
BBC
.125 dB
VU
.25 dB
Example:
Using the Extended VU scale, a meter calibrated for a +4 dBu nominal
level will actually turn the zero LED segment of the level meter on at
+3.5 dBu (and so all segments will turn on at 0.5 dBu before that
segment’s scale indication.
