SRS Labs SR560 - Manual (Page 11)

OPERATION AND CONTROLS
7
Figure 2: SR560 Front Panel
FRONT PANEL OPERATING SUMMARY
The operation of the SR560 Low-Noise
Preamplifier has been designed to be as
simple as possible. The effect of each
keypress on the front panel is reflected in
the change of a nearby LED. The front
panel LED’s will remain lighted at all times
unless dip switch SW601 (accessible
through the bottom cover of the unit)
positions 3 and 4 are placed in the "off"
position. All front panel functions can be
controlled through the rear-panel RS-232
interface.
Power
The SR560 is turned on by depressing the
POWER switch. When disconnected from
AC power, the unit will operate for
approximately 15 hours on internal sealed
lead-acid batteries. Up to 200 mA of
unregulated battery power is available at the
rear panel banana jacks as long as the
power switch is in the ON position. Battery
life will be reduced when the unit is
providing external power through the rear
panel jacks. When operating on batteries,
the front panel "BATT" indicator will be
lighted. As the batteries near exhaustion,
this indicator will change from green to red,
indicating that the unit should be connected
to AC power to charge the batteries.
When connected to an AC power source,
amplifier power is derived from regulated
line power, and the internal batteries are
automatically charged. When operating on
AC power, the front panel "LINE" indicator is
on to indicate the source of amplifier power.
Charging status is indicated on the rear
panel by the "CHARGE" and "MAINTAIN"
LED indicators.
Source
There are two input connectors located in
the SOURCE section of the front panel.
The pushbutton located between them
selects either single-ended (A or B) or
differential (A-B) inputs.
The A and B inputs are voltage inputs with
100 M
Ω, 25 pF input impedance. Their
connector shields are completely isolated
from chassis ground, but can be made