9
English
no impact on sonic performance. Instead, the
protection circuit monitors the temperature of
the output devices and shuts down the ampli-
fier if temperatures exceed safe limits.
In addition, the RKB-2100 includes overcur-
rent protection which operates only when
load impedance drops too low.
Should a faulty condition arise, the amplifier
will stop playing and the PROTECTION LED
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. When
you turn the amplifier back on, the protec-
tion circuit will automatically reset and the
PROTECTION LED should go out.
In most cases, the protection circuitry activates
because of a fault condition such as shorted
speaker wires, or inadequate ventilation
leading to an overheating condition. In very
rare cases, highly reactive or extremely low
impedance speaker loads could cause the
protection circuit to engage.
Signal Connections
The RKB-2100 provides standard conventional
input connections — unbalanced RCA type
connections as found on nearly all audio
equipment. In addition, there is a pair of
SIGNAL OUTPUT LINK connections for pass-
ing the unchanged input signal on to another
audio component.
RCA Inputs
See Figure 2
These RCA inputs accept audio signals from
preamplifiers or surround sound processors.
Use high quality audio interconnect cables
for best performance.
Connect the left channel output of your pre-
amp to the LEFT INPUT on the RKB-2100.
Connect the right channel of your preamp
to the RIGHT INPUT.
Input Level Controls
Two controls on the front panel, one for each
channel, provide input level adjustments. These
allow you to adjust the gain of the amplifier
to match other components in the system.
The L level control changes the gain of the
left channel; the R level control changes the
right channel.
To adjust these controls, use a small, flat-
blade screwdriver. Turn the control clockwise
to increase gain. Turn counterclockwise to
reduce gain.
For easier adjustment, install the supplied vol-
ume control knobs by gently pressing them
onto the control shafts. Alternatively, you can
prevent inadvertant adjustment by installing
the supplied rubber plugs to conceal the vol-
ume controls.
Signal Output Link
This pair of RCA connections can be used to
pass the unprocessed input signals to another
audio component, for example to “daisy-
chain” an additional amplifier to drive a
second set of speakers. Any INPUT SIGNAL
is also available at these LINK outputs.
Speakers
The RKB-2100 has two pair of speaker con-
nectors, one pair for each channel.
Speaker Selection
The nominal impedance of the loudspeaker(s)
connected to the RKB-2100
should be a
minimum of 4 ohms. When driving multiple
pairs of speakers connected in parallel, the
effective impedance the amplifier sees is cut
in half. For example, when driving two pair
of 8 ohm speakers, the amplifier sees a 4
ohm load. When driving multiple speakers
in parallel, select speakers with a nominal
impedance of 8 ohms or higher.
Speaker Wire Selection
Use insulated two-conductor stranded wire
to connect the RKB-2100 to the speakers.
The size and quality of the wire can have
an audible effect on the performance of the
system. Standard speaker wire will work,
but can result in lower output or diminished
bass response, particularly over longer dis-
tances. In general, heavier wire will improve
the sound. For best performance, you may
want to consider special high-quality speak-
er cables. Your authorized Rotel dealer can
help in the selection of appropriate cables
for your system.
Polarity and Phasing
The polarity or positive/negative orientation
of the connections for every speaker and am-
plifier connection must be consistent so all the
speakers will be in phase. If the polarity of
one connection is mistakenly reversed, bass
output will be very weak and stereo imaging
degraded. All speaker wire is marked so you
can identify the two conductors. There may be
ribs or a stripe on the insulation of one conduc-
tor. The wire may have clear insulation with
different color conductors (copper and silver).
There may be polarity indications printed on
the insulation. Identify the positive and nega-
tive conductors and be consistent with every
speaker and amplifier connection.
