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The two 150-ohm windings may be used separately as t w o
isolated 150-ohm outputs. Terminals 1 and 2 , and 3 and 4 will
each provide a 1507600-ohm o u t p u t when the strapping is
removed. When using dual outputs, the mixer o u t p u t levels will
each be reduced by approximately 6 d B . Additional amplification
may be necessary t o insure sufficient gain under these operating
conditions.
Dual Balanced
Outputs
Unbalanced—The transformer can be bypassed t o achieve an
unbalanced 600-ohm o u t p u t at the phone jack marked " 6 0 0 0
Direct." The jack can also be used-to feed another bridging input
when the balanced 600-ohm line is being used f o r other service.
M o n i t o r — T h e o u t p u t of the monitor amplifier is available on the
f r o n t panel and the phone jack marked " M o n i t o r " on the rear
panel. The o u t p u t signal is unbalanced and unequalized for use
w i t h a 600-ohm load.
Grounding
Input—Each microphone circuit is grounded t o the chassis at the
printed circuit board input. A n y additional connection between
the circuit and chassis or ground may cause h u m .
Output—When the balanced o u t p u t of the 5306 is connected t o
a power amplifier that does not have an isolation transformer,
the circuit-to-chassis connection at the power amplifier must be
removed. However, it is necessary t o make sure that the t w o chassis
remain electrically connected. If the*chassis are mounted in the
same rack cabinet or if both units have 3-wire power cords, this
condition will be met. A binding post is provided f o r use in the
event that no other ground connection exists. When the output trans-
former has been bypassed and the 5306 is used w i t h a device that
does not have an input transformer, the shield o f the connecting
cable must be grounded at both ends.
System Gain Adjustment
To insure that o p t i m u m signal-to-noise ratios are maintained
when the 5306 is used w i t h additional equipment between
it and the power amplifier, the gain of the auxiliary devices
must be adjusted so that the 5306 is allowed to run at normal
levels, i.e. 0 to +8 d B m . If any of these devices do not have
input attenuators, then a fixed network must be constructed
or a variable attenuator provided. Extra gain in these devices
must be individually attenuated and the final system gain
setting made at the power amplifier gain control. Care must
be taken t o insure that no component is being overdriven.
Operation
Master Gain—The Master Gain allows the operator to adjust
the level of ail inputs simultaneously. It is a feedback control
that prevents overdriving o f the mixer circuits and the internal
amplification stages.
150/600 ft #1
Mixing Controls—The program and microphone controls should
be positioned at " 5 " for average input signal levels. The V U
meter has been calibrated t o indicate approximately 0 V U at a
line level of +8 d B m ; an access hole is provided on the t o p cover
for readjustment. Amplifiers that f o l l o w the 5306 must have
their attenuation controls properly set to keep f r o m over-
driving the system. It should be remembered that the 5306 is
capable of producing +24 d B m before audible clipping.
150/600n#2
•
The microphone channel overload indicators w i l l operate when
the signal peaks are 3 dB below clipping; the input level at
which this occurs is dependent upon the setting of the channel
gain c o n t r o l . As an approximation, at a setting o f " 2 " , a
-2 d B m level will clip; while at the maximum setting, the clipping
level will be -22 d B m . Therefore, loss pad insertion is usually
not necessary t o attenuate a high level input signal. The indicator
circuit is designed t o produce noticeable flasher activity before
clipping occurs and before distortion reaches audible levels.
This progressive warning function allows the operator ample
time to make any necessary gain adjustments.
Equalizer Controls—The detented equalizer controls are marked
in 3 dB steps of boost and cut at 20 Hz and 20 kHz to a maxi-
mum of + 15 d B . They do not affect midrange program
material, nor do they affect the monitor o u t p u t .
Monitor Gain—Since the f r o n t and rear monitor outputs are
paralleled, their- levels are adjusted simultaneously by a single gain
control. Monitor o u t p u t is not affected by the Equalizer controls.
Equalization—
below 300 Hz and above 2000 Hz. Note that they do not
midrange
5
The Equalizer
controls
program
material.
affect output
of the 5306
affect
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