Thump th-15a, Owner'S Manual

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11. Line Cord Socket and Fuse
Connect the detachable line cord to this IEC socket
securely, and plug the other end into your AC outlet.
Make sure the AC power is matched to the AC power
indicated on the rear panel (under the IEC socket).
The fuse is located behind the fuse cover, at the
bottom of the IEC socket. See the “Troubleshooting”
section on page 9 for information about replacing
the fuse.
Protection Circuits
There are several protection mechanisms
designed into the TH-15A to safeguard
the loudspeakers and amplifiers from
inadvertent damage.
CAUTION: The protection
circuits are designed to
protect the loudspeakers
under reasonable and sensible
conditions. Should you choose
to ignore the warning signs
(i.e., frequent OL LED indications, excessive
distortion), you can still damage the speakers
in the TH-15A by overdriving them past the
point of amplifier clipping. Such damage is
beyond the scope of the warranty.
Overexcursion Protection
A 12 dB/octave high-pass filter at 40 Hz just prior
to the low-frequency amplifier prevents very low
frequencies from being amplified. Excessive low-
frequency energy below 40 Hz can damage the
woofer by causing it to “bottom out,” also known as
overexcursion, which is equivalent to a mechanical
form of clipping.
Thermal Protection
All amplifiers produce heat. The TH-15A is designed
to be efficient both electrically and thermally.
The amplifier module is mounted on a large
heatsink, which is cooled by convection where cool
air is drawn through it’s fins, carrying the heat away.
In order for this convection cooling to work efficiently,
it is important to provide adequate airspace behind
the loudspeaker. When you position the TH-15A, we
recommend leaving at least six inches of air space
behind it.
• If for some reason the heatsink gets too hot, a
built-in thermal switch activates and turns off the
amplifier. This protection operates independently
for the low-frequency and high-frequency
amplifiers. Therefore, it is possible for only the low
frequency or high frequency amplifier to shut
down while the other remains on.
• When the heatsink cools down to a safe
temperature, the thermal switch resets and normal
operation resumes.
• If the heatsink temperature again gets too hot, the
shutdown process repeats. Should this happen,
make sure that airflow to the rear of the cabinet
is not restricted. If the ambient air temperature
is very warm, try pointing a small fan toward the
heatsink to increase the airflow through the fins.
Driver Protection
Each driver has its own compression circuit, which
helps protect them from damaging transient peaks.
The compressors are designed to be transparent and
are not noticeable under normal operating conditions.
Input Signal Wiring
You should use high-quality, shielded
cable to connect the signal source to the IN
jack on the TH-15A.
• Foil shielded cables, such as Belden 8451,
8761, or 9501 are commonly used for
studio wiring.
• Microphone cables work well.
• The better the shield, the better the
immunity from externally induced noise
(like EMI and RFI). Route the cable away
from AC power cords and outlets. These
are common sources for hum in an audio
signal. You can purchase quality cables
from your Mackie dealer.
Placement
The TH-15A loudspeaker is designed to sit
on the floor or stage. It can be pole-mounted
via the built-in socket on the bottom of
the cabinet. Be sure the pole is capable of
supporting the weight of the TH-15A.
WARNING: The cabinet has
no rigging points and is not
suitable for rigging.
NEVER
attempt to suspend
the TH-15A by its handles.
As with any powered components,
protect them from moisture. If you are
setting them up outdoors, make sure they
are under cover if you expect rain.