Ac power and control – ROTEL RKB-650 User Manual

Page 12

RKB-650 Six Channel Power Ampliﬁer

• With the switch in the SIGNAL

SENSE position, the ampliﬁer turns on
automatically when a signal is detected
at the inputs. The ampliﬁer will go into
standby mode several minutes after no
signal is no longer present. The front pan-
el power switch overrides this function.
It must be ON for the signal sensing to
work. Turning the switch OFF cuts power
to the ampliﬁer, regardless of whether or
not a signal is present.

• With the switch in the 12V TRIG

position, the ampliﬁer is turned on auto-
matically when a 12 volt trigger signal is
present at the 12V TRIG input to the left of
the switch. The ampliﬁer goes into standby
mode if the +12 volt signal is not present.
The front panel POWER SWITCH over-
rides this function. It must be ON for the
+12V trigger to work. Turning the switch
OFF cuts power to the ampliﬁer, regard-
less of whether or not a trigger signal is
present.

12V Trigger Input

An input jack for connecting the wires car-
rying a +12 volt trigger signal from a Rotel
preamp or surround sound processor to turn
the ampliﬁer on and off. To use this feature
the adjacent slide switch must be placed to
the left position (see previous section).

The TRIGGER INPUT accepts any control
signal (AC or DC) ranging from 3 volts to
30 volts. Using a cable with mono 3.5 mm
mini-plugs on both ends. The +12 V DC sig-
nal appears at the “tip” connector.

12V Trigger Output

The 12V TRIG jack labeled OUT is used to
pass the remote turn-on signal to a second
Rotel ampliﬁer. Any 12V Trigger signal at
the INPUT jack will be passed through to
the OUT jack.

Circuit Breaker

A 16 amp circuit breaker on the rear panel
protects the ampliﬁer’s electrical circuity.
Generally, the circuit breaker will only open
under a fault condition which results in exces-
sive current draw. To reset the circuit breaker,
press the button. Should it repeatedly open,
contact your authorized Rotel dealer for trou-
bleshooting assistance.

Protection Indicators

A thermal protection circuit protects the am-
pliﬁer against potential damage in the event
of extreme or faulty operating conditions. Un-
like many designs, the RKB-650’s protection
circuit is independent of the audio signal and
has no impact on sonic performance. Instead,
the protection circuit monitors the tempera-
ture of the output devices and shuts down the
ampliﬁer if temperatures exceed safe limits.

In addition, the RKB-650 includes overcurrent
protection which operates only when load
impedance drops too low.

Should a faulty condition arise, the ampli-
ﬁer will stop playing and one or more of
the PROTECTION LEDS on the front panel
will light.

If this happens, turn the ampliﬁer off, let it
cool down for several minutes, and attempt
to identify and correct the problem. There are
independent PROTECTION LEDS for each
pair of channels which may help in trouble-
shooting the cause of the problem. When
you turn the ampliﬁer back on, the protec-
tion circuit will automatically reset and the
PROTECTION LEDS should go out.

In most cases, the protection circuitry acti-
vates because of a fault condition such as
shorted speaker wires, or inadequate venti-
lation causing an overheating condition. In
very rare cases, highly reactive or extremely
low impedance speaker loads could cause
the protection circuit to engage.

AC Power and Control

AC Power Input

Your RKB-650 is conﬁgured at the factory
for the proper AC line voltage in the country
where you purchased it (USA: 120 volts/60
Hz, Europe: 230 volts/50 Hz). The AC line
configuration is noted on a label on the
back panel.

The RKB-650 is supplied with the proper AC
power cord. Use only this cord or an exact
equivalent. Do not modify the supplied cord.
Do not use an extension cord.

Be sure the power switch on the front panel
of the RKB-650 is turned off. Then, plug one
end of the cord into the AC power connector
on the back panel of the ampliﬁer. Plug the
other end into an appropriate AC outlet.

If you are going to be away from home for
an extended period of time, it is a sensible
precaution to unplug your ampliﬁer.

Power Switch

Indicator LED

The power switch is located on the left side
of the front panel. To turn the ampliﬁer on
(or to activate either of the optional auto-
matic power-on modes), push the switch in.
The LED indicator above the switch will light,
indicating that the ampliﬁer is turned on. To
turn the ampliﬁer off, push the button again
and return it to the out position.

Auto Turn On/Off Mode Selec-

tor

The RKB-650

provides three different op-

tions for manual or automatic power on/off
operation. These modes are selectable us-
ing a three-position slide switch on the back
panel as follows:

• With the switch in the OFF position,

the ampliﬁer is turned on or off manually
using the front panel power switch. Also
use this mode if you are using a switched
AC outlet to control power to the ampli-
ﬁer.