A SYSTEMS SR707 User Manual page 7

100 volt line output connection
Bridge Mono Configuration for Audio Transformer Outputs
1. For driving 140V or 200V distributed lines, the amplifier
must be set to bridge mono mode�
2. Connect the signal to channel 1's input only� Do not
connect an input signal to channel 2�
3. Use only channel 1's gain control to set the level�
Both channels signal and clip indicators should flash
identically when the amplifier is operating.
140 volt line output connection, bridge mono mode
200 volt line output connection, bridge mono mode
SR703 | SR707 CONTRACTOR AMPLIFIER
Parallel Mono Configuration
The "Parallel mode" ties the two channel inputs together
so that both are driven by the same signal, without the
need for external jumpers or wiring� After the inputs, both
channels operate independently� Although they carry the
same signal, each channel's gain control only affects their
respective channels and must be used separately� Please
refer to the Rear Panel section on page 5�
Low-Impedance and Distributed Speakers
If your application calls for connection of an 8 ohm speaker
and a distributed line to the same amplifier channel, the
SR703 and SR707 are among the few amplifiers available
that can do that� However, since most of the audio power
is drawn by the direct-connected speaker, you must
derate the distributed line; and the distributed line should
have a total power load of no more than one-fourth of the
amplifiers normal distributed line power rating.
Calculate maximum allowable distributed line load with
n
a known low-impedance load with this formula:
MaxTOP = [MaxRatedPL - ((2 x MaxRatedPL)/Impedance)]/2
MaxTOP is the sum of the power taps of the speakers
connected to the Audio Transformer outputs� MaxRatedPL
is the maximum rated power of the amplifier into a two
ohm load� Impedance is the load impedance connected to
the direct outputs�
Example: One channel of the SR703 has an 8-ohm load
connected to the Direct (low impedance) output� Then the
maximum power left available to drive a distributed line is:
TO 140V LINE
TO 200V LINE
7
MaxTOP = [240-((2x240/8)/2)] = 90 Watts
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