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AMP2A-VTR and AMP2A-VTR2 User Manual P/N 821580 REV-B
The standard scale used on the AMP2A-VTR and AMP2A-VTR2 level meters (53-segment) is the Extended VU scale (see diagram
below). However, if alternative scale characteristics are selected for the level meters using the Level Meter Internal 10-Position DIP
Switch (page 23), it is recommended that a label with the appropriate scale be applied to the front panel LED bargraph level meters. See the
diagram below for scale comparison. Scale selection includes the Extended VU (standard Analog), VU, BBC, NORDIC, DIN, and
Custom (not shown) scales. Contact Wohler Technologies for information about alternative scale labels.
0
2
4
7
10
13
16
18
20
22
25
28
31
34
38
42
46
51
56
66
AES
(Digital)
Scale
(standard)
Since it is sometimes helpful to observe phase relationships between two signals being monitored, a Phase Correlation
feature can be implemented within the lower section of an existing bargraph pair in the 53-segment LED bargraph level
meters used in the AMP2 units. This feature may be turned ON and OFF by setting the Level Meter Internal 10-Position
DIP Swich module (page 18). Below is an illustration of the level meter bargraphs with the Phase Correlation label applied.
When the audio level in BOTH channels is high enough, the Phase Correlation display occupies the lower few segments of
both bargraphs of a stereo pair. Behavior of the Phase Correlation indication is as follows:
Positive correlation = ascending AMBER bar in the right bargraph
Negative correlation = ascending RED bar in the left bargraph
The bottom nine (9) segments are used by the 53-segment LED bargraph display for Phase Correlation indication. One
additional segment above the active correlation region is always OFF, to serve as a marker. The Phase Correlation display
is visible ONLY so long as the VU audio level is above this blank segment (tenth from the bottom).
20
Level Meter Alternative Scales
15
+3
12
+2
8
6
+1
4
2
0
0
2
-1
6
-2
10
-3
12
-5
15
18
-7
22
26
-10
30
-15
35
40
-20
50
Extended VU
VU
(Analog)
Scale
Scale
(standard)
Level Meter Phase Correlation Feature
-1
.5
0
© 2004 Wohler Technologies Inc. ALL rights reserved
+12
7
+9
+6
6
+3
T
-3
5
-6
-9
-12
4
-15
-18
3
-21
-24
-27
2
-30
-33
-36
1
-42
BBC
NORDIC
Scale
Scale
15
12
8
6
4
2
0
2
6
10
12
15
18
22
26
30
+1
35
.5
40
50
0
correlation
Section 3: Technical Information
+5
0
-5
-10
-20
-30
-40
-50
DIN
Scale
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