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CF SERIES LOUDSPEAKERS
3
1. Your receiver or amplifier minimum load
impedance. Impedance is always expressed
in ohms and can be found in the owner's
manual that came with your unit. For
example, the following are typical entries
in receiver/amplifier owner's manuals:
A. 100 watts RMS into 8 ohms, both
channels driven, 20 – 20kHz with less
than 0.02%THD
B. 160 watts RMS into 4 ohms, both
channels driven, 20 – 20kHz with less
than 0.02% THD.
2. The nominal impedance of the sec-
ond set of speakers. A pair of CF Series
speakers when combined with another
pair of 8-ohm speakers will present an
impedance to the receiver/amplifier that is
approximately 4 ohms. This speaker com-
bination can be used with the receiver/
amplifier cited in B above. If the receiver/
amplifier has a specification similar to that
shown in A above, or if your second set of
speakers has an impedance other than
8 ohms, you must consult the receiver/
amplifier manufacturer for clarification.
POWER HANDLING
Thanks to their high efficiency, JBL
CF Series loudspeakers will produce
reasonable volume levels in a room of
moderate size with very little amplifier
power. However, using a small amplifier to
obtain the desired volume listening levels
may lead to overdriving the amplifier. This
will generate high distortion levels and may
cause damage to your loudspeaker. For
the best performance, an amplifier should
be selected with an output rating that is
greater than the maximum power that will
be used. This margin of reserve power will
ensure that the amplifier will not attempt to
deliver more power than its design allows.
However, the power amplifier's power rat-
ing per channel must not exceed the maxi-
mum recommended amplifier power for
that specific loudspeaker model. Please
see the specifications section for details.
Following these guidelines will provide
distortion-free sound reproduction and
long loudspeaker life.
TROUBLESHOOTING
Most "malfunctions" end up being traced
to connections or switch settings. To
avoid packing up correctly functioning
speakers and sending them off, only to
find that they're not really at fault, check
the following tips first, before requesting
service.
No sound at all or very faint sound
from both speakers
1. Amp/receiver tape monitor button
pushed in while using CD, FM or phono
inputs.
2. Wrong speaker switch, "A" or "B"
speaker output.
3. Sound source (CD, cassette deck,
turntable) not turned on, not activated,
not hooked up or not selected on
amp/receiver front panel.
4. CF120: Blown fuse (see Fuse
Replacement).
No sound from one speaker
1. Balance control turned all the way left
or right.
2. Speaker wire has become disconnected.
3. One of the connections between sound
source and amp/receiver is faulty or has
become disconnected.
Both speakers play at low volumes
but shut off as volume is increased OR
sound turns on and off intermittently
1. A few strands of speaker wire may be
shorting out. Recheck the connections.
2. More than 1 pair of speakers are
connected to the amp and the total
impedance is too low. Recheck the
minimum impedance requirements of
the amp.
Bass is very weak AND/OR sound
seems to come from each speaker
separately, without creating a stable
stereo image between the speakers.
1. The polarity (+&–) of one speaker has
been reversed relative to the other.
Double check connections.
2. Speakers are too far away from back
and side walls or too far apart.
Experiment again with the speaker
placement. If you are still encountering
problems, consult your JBL dealer.
CF-Owner's Manual 7/28/98 9:51 AM Page 3