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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.
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.
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.
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.
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.
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 indication of how loud the
Maintaining Connections
Amplifier Power Recommendations
5
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