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7
English
Speaker Connection
Speaker Selection
We recommend using loudspeakers with a
nominal impedance of 4 ohms or higher with
the RB-03. You should exercise some caution
in driving multiple pairs of speakers in par-
allel configuration, because the effective im-
pedance 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,
it is recommended that you select speakers with
a nominal impedance of 8 ohms or higher.
Speaker impedance ratings are less than pre-
cise. In practice, very few loudspeakers will
present any problems for the RB-03. See your
authorized Rotel dealer if you have any ques-
tions.
Speaker Wire Selection
Use insulated two-conductor stranded wire to
connect the RB-03 to the speakers. The size
and quality of the wire can have an audible
effect on the performance of the system. Stan-
dard speaker wire will work, but can result
in lower output or diminished bass response,
particularly over longer distances. In general,
heavier wire will improve the sound. For best
performance, you may want to consider special
high-quality speaker cables. Your authorized
Rotel dealer can help in the selection of ap-
propriate cables for your system.
Polarity and Phasing
The polarity — the positive/negative orien-
tation of the connections — for every speaker
and amplifier connection must be consistent
so all the speakers will be in phase. If the po-
larity of one connection is mistakenly reversed,
bass output will be very weak and stereo im-
aging degraded. All wire is marked so you
can identify the two conductors. There may
be ribs or a stripe on the insulation of one con-
ductor. 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 negative
conductors and be consistent with every
speaker and amplifier connection.
Stereo Speaker Connection
The RB-03 has two pairs of color coded binding
posts on the back panel. These connectors ac-
cept bare wire, connector lugs, or dual ba-
nana type connectors (except in the European
Community countries where their use is not
permitted).
Route the wire from the RB-03 to the speak-
ers. Give yourself enough slack so you can
move the components enough to allow access
to the speaker connectors.
If you are using dual banana plugs, connect
them to the wires and then plug into the backs
of the binding posts. The hexagonal thumb-
screws of the binding posts should be screwed
in all the way (clockwise).
If you are using terminal lugs, connect them
to the wires. If you are attaching bare wires
directly to the binding posts, separate the wire
conductors and strip back the insulation from
the end of each conductor. Be careful not to
cut into the wire strands. Unscrew (turn coun-
terclockwise) the binding post hexagonal
thumbscrews. Place the connector lug or wire
around the binding post shaft. Turn the hex-
agonal thumbscrews clockwise to clamp the
connector lug or wire firmly in place.
Note: Be sure there are no loose wire
strands that could touch adjacent wires or
connectors.
Bridged Mono Operation
[See Figure 3 for bridged operation
jumper setting and connection illus-
tration.]
The two channels of the RB-03 can be
“bridged”. In this configuration the single
channel produces a massive 180 watts! This
feature allows you to increase the overall power
output of your system by bridging the RB-03
and adding a second bridged RB-03. Or the
RB-03 is bridged to drive a monophonic sub-
woofer. Note however that when the RB-03
is bridged the speaker connected to it must
have an impedance of 8 ohms or more.
In order to use the RB-03 in bridged mode,
three “jumper” connectors inside the ampli-
fier must be moved from one set of pins to an-
other. This task should be done by a quali-
fied technician. See your authorized Rotel
dealer. In addition the RB-03 is connected to
the other components in a different way. When
the RB-03 is setup for bridged operation the
Bridged Mono indicator light
on the front
panel will light.
Resetting Jumpers
Before opening the RB-03 cabinet to reset
the jumpers, the power cord must be un-
plugged from the wall. DO NOT OPEN
THE CABINET OF THE RB-03 BEFORE THE
POWER CORD HAS BEEN UNPLUGGED
FROM THE WALL. FAILURE TO DO SO
WILL EXPOSE YOU TO HAZARDOUS
VOLTAGES.
After the power cord has been unplugged,
remove the screws that hold the cabinet cover
in place and slide the cover off the amplifier.
Locate the three jumper pin blocks labeled
S 601, S 602 and S 603. The factory stan-
dard (stereo) position of the jumpers is on pins
1 and 2 of each block. There is a * mark on
the circuit board next to this position. To con-
vert the RB-03 to bridged mono move all three
jumpers so they are on pins 2 and 3 of each
jumper pin block. Replace the cover of the
cabinet. Do not plug the RB-03 power
cord back into the wall outlet until
the cabinet cover has been replaced.
Input Connection
When using the RB-03 in bridged mono mode,
connect the cable from the preamplifier out-
put to the left input. No connection is made
to the right input.
Bridged Speaker Connection
When using the RB-03 in bridged mono mode,
the wire to the speakers is connected to the
positive terminals of the left and right chan-
nels. Connect the wire that goes to the posi-
tive terminal of the speaker to the positive ter-
minal of the left channel of the RB-03. Con-
nect the wire that goes to the negative termi-
nal of the speaker to the positive terminal of
the right channel of the RB-03. No connec-
tions are made to the negative terminals of
the RB-03.