JBL 250 Ti (serv.man2) User Manual / Operation Manual ▷ View online
5
same type of wires may be used for both low-frequency
and high-frequency sections to reduce wire effects (resis-
tance, inductance, etc.) and to avoid intermodulation of
low and high frequencies.
and high-frequency sections to reduce wire effects (resis-
tance, inductance, etc.) and to avoid intermodulation of
low and high frequencies.
In some systems, using specialized wires for low-fre-
quency and high-frequency sections may yield excellent
results. In either case, low-frequency cables should be as
short as possible, and the left and right cables for each
section must be the same length. CAUTION: Never con-
nect two amplifier channels to the same loudspeaker
without first removing the strapping bars. Operating two
amplifier channels with the bars in place will seriously
damage the amplifiers and void the warranty.
results. In either case, low-frequency cables should be as
short as possible, and the left and right cables for each
section must be the same length. CAUTION: Never con-
nect two amplifier channels to the same loudspeaker
without first removing the strapping bars. Operating two
amplifier channels with the bars in place will seriously
damage the amplifiers and void the warranty.
The bi-wire option also enables you to power the
system with two amplifiers. Four identical amplifiers (or
two dual-channel units) may be used, although specialized
low- and high-frequency amplifiers offer clear advantages.
Your JBL 250Ti Jubilee dealer can recommend the amplifi-
cation that will best suit your needs. In all cases, the left
and right amplifiers for each section must be identical.
Make sure that the input sensitivity of the two amplifiers is
equal, or that input level controls are provided to maintain
the proper low-to-mid/high balance. If you are using two
identical stereo amplifiers, you may locate one near each
loudspeaker and drive low- and high-frequency sections
through short wire runs.
two dual-channel units) may be used, although specialized
low- and high-frequency amplifiers offer clear advantages.
Your JBL 250Ti Jubilee dealer can recommend the amplifi-
cation that will best suit your needs. In all cases, the left
and right amplifiers for each section must be identical.
Make sure that the input sensitivity of the two amplifiers is
equal, or that input level controls are provided to maintain
the proper low-to-mid/high balance. If you are using two
identical stereo amplifiers, you may locate one near each
loudspeaker and drive low- and high-frequency sections
through short wire runs.
Input polarity must be the same for both low- and
high-frequency sections. Some amplifiers invert polarity.
If the polarity is reversed to one section, a discontinuity
in response will be apparent in the crossover region.
If a problem is suspected, reverse the polarity to either
low- or high-frequency sections of both loudspeakers.
Amplifier polarity markings may not ensure correct
polarity connections.
If the polarity is reversed to one section, a discontinuity
in response will be apparent in the crossover region.
If a problem is suspected, reverse the polarity to either
low- or high-frequency sections of both loudspeakers.
Amplifier polarity markings may not ensure correct
polarity connections.
Maintaining Connections
All connections should be inspected and cleaned or
remade periodically. Frequency of maintenance depends
on the metals involved in the connection, atmospheric
conditions and other factors. Consult your dealer for
specific recommendations.
remade periodically. Frequency of maintenance depends
on the metals involved in the connection, atmospheric
conditions and other factors. Consult your dealer for
specific recommendations.
Amplifier Power Recommendations
The 250Ti Jubilee is capable of handling 200 watts contin-
uous (based on an 8-hour test using broadband noise
shaped to simulate the power distribution of music) with
peaks of up to 800 watts (indicating the system’s ability to
handle transient peaks well above average power levels).
Unfortunately, amplifier power ratings generally refer only
to continuous, steady-state power levels measured with a
test signal, and are only an
uous (based on an 8-hour test using broadband noise
shaped to simulate the power distribution of music) with
peaks of up to 800 watts (indicating the system’s ability to
handle transient peaks well above average power levels).
Unfortunately, amplifier power ratings generally refer only
to continuous, steady-state power levels measured with a
test signal, and are only an
indication of how loud the
JBL2516 250TIjubileemanual 7/20/98 11:19 AM Page 5
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system will play without distortion. More important than
the power rating is the quality of
the power rating is the quality of
sound the amplifier is
capable of, or its
dynamic power capability. Since am-
plifier specifications are not a reliable indicator of sound
quality, an amplifier should be chosen only after careful
listening. If it can achieve the desired volume level without
distortion, then the amplifier has sufficient power, regard-
less of its rating. Your JBL 250Ti Jubilee dealer can make
recommendations and arrange auditions to help you select
suitable amplification for your system.
quality, an amplifier should be chosen only after careful
listening. If it can achieve the desired volume level without
distortion, then the amplifier has sufficient power, regard-
less of its rating. Your JBL 250Ti Jubilee dealer can make
recommendations and arrange auditions to help you select
suitable amplification for your system.
NOTE: If four amplifier channels are used, the high-fre-
quency amplifier may be up to 6dB less powerful than the
low-frequency amplifier. This is because the low-frequency
section requires approximately four times the power of the
high-frequency section, due to the power versus frequen-
cy distribution of music. For example, if a 200-watt low-
frequency amplifier is used, a 50-watt high-frequency
amplifier will clip, or “run out of power” at approximately
the same level, when playing music.
low-frequency amplifier. This is because the low-frequency
section requires approximately four times the power of the
high-frequency section, due to the power versus frequen-
cy distribution of music. For example, if a 200-watt low-
frequency amplifier is used, a 50-watt high-frequency
amplifier will clip, or “run out of power” at approximately
the same level, when playing music.
Do not use fuses or circuit breakers of any kind
between the amplifier and loudspeakers. Such devices will
seriously degrade the sound quality and do not ensure
protection from loudspeaker damage. The key to safe
operation is having adequate amplifier power to avoid dis-
tortion at the highest sound levels required.
seriously degrade the sound quality and do not ensure
protection from loudspeaker damage. The key to safe
operation is having adequate amplifier power to avoid dis-
tortion at the highest sound levels required.
Biased Crossover Battery Replacement
The crossover network in the 250Ti Jubilee uses a 9V
battery to maintain a charge on the capacitors used in the
midrange, high-frequency and ultrahigh-frequency circuits.
The purpose of this charge is to allow the capacitors to
operate in a “class A” mode. This treatment gives the sys-
tem greater detail and spatial properties than a traditional
network. The current drain on the battery is extremely
small. The average battery life is 3 to 4 years. When
replacement is required, remove the two top center
screws on the network cup and carefully lift off the curved
battery cover. The battery is held in a clip on the left side
of the network. Simply remove the old battery and replace
it with a new one. Reinstall the cover and screws.
battery to maintain a charge on the capacitors used in the
midrange, high-frequency and ultrahigh-frequency circuits.
The purpose of this charge is to allow the capacitors to
operate in a “class A” mode. This treatment gives the sys-
tem greater detail and spatial properties than a traditional
network. The current drain on the battery is extremely
small. The average battery life is 3 to 4 years. When
replacement is required, remove the two top center
screws on the network cup and carefully lift off the curved
battery cover. The battery is held in a clip on the left side
of the network. Simply remove the old battery and replace
it with a new one. Reinstall the cover and screws.
BATTERY
BI-AMP
High Frequency
Low Frequency
NORMAL/
BI-WIRE
BI-WIRE
JBL2516 250TIjubileemanual 7/20/98 11:19 AM Page 6
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Grille
Loudspeaker grilles protect the transducers and enhance
the appearance of the system in many rooms. However,
even the most acoustically transparent grille affects the
sound. On the 250Ti Jubilee, the effect is minor, particular-
ly for casual listening or background music, but apparent.
For serious listening in circumstances where damage is
unlikely (i.e., when small children are not present), we
recommend that the grille be removed.
the appearance of the system in many rooms. However,
even the most acoustically transparent grille affects the
sound. On the 250Ti Jubilee, the effect is minor, particular-
ly for casual listening or background music, but apparent.
For serious listening in circumstances where damage is
unlikely (i.e., when small children are not present), we
recommend that the grille be removed.
General Care
The 250Ti Jubilee is finished in high-gloss lacquer. The
beautiful, deep-gloss finish is the result of a meticulous
multistep painting and polishing procedure. Treat the sur-
face very carefully to avoid scratching the finish. Use only
lint-free cotton cloths for dusting. To remove fingerprints
and smudges, an ammonia-free window cleaner may be
used; apply a small amount to a lint-free cotton cloth and
gently clean the surface. Never use any abrasive cleaners
or strong chemicals to clean the enclosure. In case of
deep scratches or damage, please consult a qualified
furniture repair shop.
beautiful, deep-gloss finish is the result of a meticulous
multistep painting and polishing procedure. Treat the sur-
face very carefully to avoid scratching the finish. Use only
lint-free cotton cloths for dusting. To remove fingerprints
and smudges, an ammonia-free window cleaner may be
used; apply a small amount to a lint-free cotton cloth and
gently clean the surface. Never use any abrasive cleaners
or strong chemicals to clean the enclosure. In case of
deep scratches or damage, please consult a qualified
furniture repair shop.
The grille may be gently vacuumed in the removed
position only. Stains may be removed with an aerosol
cleaner, following its instructions. Do not use solvents on
the grille.
cleaner, following its instructions. Do not use solvents on
the grille.
Service
JBL 250Ti Jubilee loudspeakers are designed to provide
years of trouble-free service. No maintenance is required.
If a problem is suspected, first make sure that all connec-
tions are properly made and clean. If a problem exists in
one loudspeaker, reverse the speaker wires to the left and
right system. If the problem remains in the same system,
then the fault is in the loudspeaker. If the problem appears
in the opposite system, the cause is in another component
or cable.
years of trouble-free service. No maintenance is required.
If a problem is suspected, first make sure that all connec-
tions are properly made and clean. If a problem exists in
one loudspeaker, reverse the speaker wires to the left and
right system. If the problem remains in the same system,
then the fault is in the loudspeaker. If the problem appears
in the opposite system, the cause is in another component
or cable.
Do not move loudspeaker cones or diaphragms by
hand. The voice coil assembly is aligned with extreme
precision and the clearance is very small. Any attempt to
move the assembly by hand can easily force the coil out of
alignment and cause distortion or failure.
precision and the clearance is very small. Any attempt to
move the assembly by hand can easily force the coil out of
alignment and cause distortion or failure.
Should your 250Ti Jubilee system ever need service,
contact the JBL dealer or distributor from whom it was
purchased. If this is not possible, write directly to the JBL
Customer Service Department, describing the problem as
fully as possible, and wait for return authorization. Do not
return products to the JBL factory without prior authoriza-
tion. Address correspondence to: JBL Customer Service,
80 Crossways Park West, Woodbury, NY 11797
Telephone: (516) 496-3400, or (800) 645-7292. Outside
the United States, contact your local JBL distributor.
purchased. If this is not possible, write directly to the JBL
Customer Service Department, describing the problem as
fully as possible, and wait for return authorization. Do not
return products to the JBL factory without prior authoriza-
tion. Address correspondence to: JBL Customer Service,
80 Crossways Park West, Woodbury, NY 11797
Telephone: (516) 496-3400, or (800) 645-7292. Outside
the United States, contact your local JBL distributor.
JBL2516 250TIjubileemanual 7/20/98 11:19 AM Page 7
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Specifications
250Ti Jubilee
Low Frequency:
360mm (14 in.)
Midrange:
200mm (8 in.)
130mm (5 in.)
130mm (5 in.)
High Frequency:
25mm (1 in.)
Titanium Dome
Titanium Dome
Frequency Response:
±2dB, 50Hz – 21kHz
Usable Response (– 6dB): 30Hz – 25kHz
Sensitivity:
Sensitivity:
89dB, 2.83 volts @ 1m
Power-Handling Capability: 200 watts continuous
800 watts peak
Nominal Impedance:
8 ohms
Crossover Frequency:
350Hz, 1.2kHz, 5kHz
JBL continually engages in research related to product
improvement. New materials, production methods and
design refinements are introduced into existing products
without notice as a routine expression of that philosophy.
For this reason, any current JBL product may differ in
some respect from its published description, but is always
warranted to equal or exceed the original design specifica-
tions unless otherwise stated.
improvement. New materials, production methods and
design refinements are introduced into existing products
without notice as a routine expression of that philosophy.
For this reason, any current JBL product may differ in
some respect from its published description, but is always
warranted to equal or exceed the original design specifica-
tions unless otherwise stated.
JBL Consumer Products
80 Crossways Park West, Woodbury, NY 11797
www.jbl.com
©
1997 JBL, Incorporated. JBL is a registered trademark of JBL, Incorporated.
Printed in USA 10/97
Part No. 250TIJUBOM
A Harman International Company
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