Pub. 42004-610L2A
Model 751-801 SmartSeries
®
Speaker Amplifier
Page: 9 of 12
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Adjustments
This assembly includes one external control that permits adjustments to be made while the assembly is
mounted in its enclosure and several internal controls that are accessible only by removing the assembly
from its enclosure.
External Adjustments
The only externally accessible user adjustment is for setting the speaker amplifier gain for the
SmartVolume™ feature, which has three components: Minimum Level, Offset Level, and VLC Level.
Although they typically require no adjustments, these volume levels can be set with the User Level
Adjustment control (labeled
USER ADJ
) located under the nameplate on the front panel, as shown in
Figure 1. Use a small flat-blade screwdriver with an insulated shaft at least 4 inches long to make
adjustments. To access the
USER ADJ
control, perform the following steps:
1.
Loosen (do not remove) the 2 screws that secure the nameplate.
2.
Pivot the nameplate counterclockwise, exposing the access hole. A guide behind the access hole
helps direct the screwdriver to the
USER ADJ
control.
3.
When you are done with the adjustment, pivot the nameplate clockwise into position, then tighten the
2 screws.
Minimum Level
The Minimum Level adjustment sets the minimum output of the speaker amplifier. The amplifier can be
set from minimum to full output (12 watts into 8 ohms) in 100 discrete steps, or to no output. The factory
default is step 20, providing 4 watts. To adjust the Minimum Level, perform the following steps:
1.
Turn
USER ADJ
fully counterclockwise and wait to hear a single beep over the associated speaker.
This switches the speaker amplifier into the Minimum Level adjustment mode. If there is an audio
signal on the page line when the amplifier enters this mode, you hear it over the associated speaker.
Otherwise, you hear an amplifier-generated test tone.
2.
Turn
USER ADJ
clockwise to the desired minimum speaker volume level.
The amplifier remains in the Minimum Level adjustment mode for as long as
USER ADJ
is varying.
After
USER ADJ
has remained stable for five seconds, the amplifier returns to its normal operating
mode.
