CONNECTION AND SET UP (cont.)
Connect shield to GND at one end only, grounding at the signal
source end is preferable. Connecting shield at only one end prevents
current flow in the shield due to differences in AC ground potential
between equipment, thus preventing ground loop-induced hum. The ALM771
input amplifier is active, balanced, and bridging.
From an UNBALANCED output source to ALM771 input:
CENTER (SIGNAL) CONDUCTOR - to T
SHIELD - to R
From ALM771 output to a BALANCED input:
OUTPUT T - to TIP or HI
OUTPUT R - to RING or LO
GND - Connect shield at ALM771 only.
From ALM771 output to an UNBALANCED input:
OUTPUT T - to center conductor
OUTPUT R - no connection
GND - to shield
The output is balanced, and is capable of driving loads of 600
Ohms and higher with low distortion. Multiple output loads can driven
but they must be high impedance.
POWER SUPPLY
Connect the power cube into a suitable power strip or socket. Take
the other end of the power wire and plug it into the rear of the ALM771
labeled POWER. Now you should see an LED lit on the front of the unit.
MONO SETUP
Adjust the INPUT SET control of the ALM771 until the center green
LED is lit with normal level program audio. This sets the input level
to the center of the gain control range. At this point the unit will
control audio levels over a +/- 15 dB input range. The display will
move up during high level passages and down during low level passages.
STEREO SETUP
READ THIS ENTIRE SECTION BEFORE MAKING ANY ADJUSTMENTS.
For stereo operation it is necessary to use two ALM771 units, one
for each channel (left and right). Be careful to wire each unit
correctly. Make sure that HI or (+) connects to T and LO or (-)
connects to R at both inputs and outputs. A reversal of polarity will
cause cancellation of any center or monaural signal. Connect shields to
GND at one end only.
ALM771.ISB
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