RCF MR44T, User Manual, Page: 11 / 16

11
ENGLISH
INPUT CABLES
For connecting the speaker use cables with an adequate cross-section. The greater the distance
between the amplifier and the speaker, the larger the connection cable cross-section should be to
limit the voltage loss along the line.
To prevent inductive phenomena from giving rise to humming or disturbance that jeopardize the
effective operation of the audio system, the speaker cables should not be run together with electrical
energy conductors, microphone cables, or low level audio lines (e.g. LINE level).
To facilitate the ‘’in phase’’ connection of the speaker, use bipolar cables that have markings to
distinguish the polarity (e.g. insulation of different colours, conductors of different colours, ect.).
To minimize the inductive effects (hum) due to coupling with surrounding electrical fields, use cables
with conductors braided together.
Pa
= Amplifier power
Pd
= Speaker power
n
= Number of speakers
Vd
= Speaker input voltage
Va
= Amplifier output voltage
Amplifier
Pa > Pd x n Va
Vd = Va
+
-
-
+ - +
Vd = Va
Fig. 3
-
+
Vd = Va
1.
a)
This rotary control selects the power tap for the
internal constant voltage transformer. Choices are
40 W, 30 W, 20 W, 10 W, 5 W and BYPASS (used for
4 ohm operation).
b)
This rotary control selects the constant voltage
distributed system in which the speaker is used.
Choices are BYPASS (used for 4 ohm operation), 0
(Off), 25V, 50V, 70V and 100V.
Note: Use a slot-head screwdriver to adjust the
rotary controls.
2.
CONNECTIONS (Fig. 2) - The spring-loaded speaker
terminals are designed to accept bare wire, up
to a maximum of 18 gauge. Strip 1/4’’ (6 mm) of
insulation off the end of the speaker wire, press in
the tab, and insert the bare wire into the hole. When
you release the tab, the wire is locked in place.
Make sure there are no stray strands of wire outside
the terminal connection.
WARNING: To prevent the risk of electrical shock,
always fit the protective cover of the terminals after
completing connections.
3.
Connect the other
conductor of the speaker to the “positive” (+)
conductor of the audio line.
4.
When making the connections, keep the following
indications in mind (Fig. 3, costant voltage).
• The input voltage selected on the speaker must
correspond with the voltage selected on the
amplifier.
• The sum of the operating power values of all the
speakers connected to the audio line must not
exceed that of the amplifier.
• To ensure correct audio reproduction, the connections
should be made “in phase”, where the +/- polarities
of the amplifier output correspond with the +/-
polarities of the speaker input.
When two speakers reproduce the same frequencies
but with phase differences, these frequencies may be
annulled. In sound systems, speakers are often situated
in adjacent positions and the sound waves produced
interact with each other. If a speaker is connected
incorrectly; i.e. the polarity of the audio line conductors
is inverted, the audio signals are transmitted with
differences in phase and correct reproduction is
therefore jeopardized.
Fig. 1
a
b
+
-
–
+
Fig. 2