NHT Powered Subwoofers owner manual Operation, Maintenance, Troubleshooting

Operation

We recommend that the Ten or Twelve power be left on, which will allow the built-in Auto Mode feature to disable the subwoofer when not in use.

Every speaker, has limits, and it's important to listen for them. Speaker damage most often results not from brief loud musical peaks, but from sustained high volume levels in some or all frequencies. For this reason, extreme volume settings and excessive bass, treble or equalizer boosts are not recommended.

If you hear unusual distortion or breakup, or notice heat coming from the woofer, decrease volume immediately, neutralize any excess bass, treble or equalizer boosts, and avoid setting any controls to similar extremes again.

Maintenance

Your Ten and Twelve is designed for years of use with no or minimal maintenance, as long as you avoid exposing it to direct sunlight, high temperatures, or moisture. Clean cabinets, when necessary, using a damp cloth or a mild, non-abrasive cleaner; to clean grilles, remove from speaker and use a soft brush or a vacuum on its lowest setting. Do not attempt to clean the actual driver.

Changing the Line Voltage Setting

The Ten and Twelve were designed to operate on two line voltage settings, 115VAC and 230VAC. In the event that it is necessary to change the line voltage setting, begin by turning the power switch to the off position. Remove all the connections from the amplifier, including the detachable power cord. Using a flat blade screw- driver, slide the switch to the correct position. Use the 115VAC position for 110 to 120 VAC, and the 230VAC position for 220 to 240 VAC. Next you will likely need a power cord that fits the AC receptacle and you will need to replace the fuse (see "Changing the Fuse" below)

Changing the Fuse

The Ten and Twelve amplifier's fuse is user-serviceable.

To replace it:

•turn the power OFF

•unplug the power cord

•remove the fuse holder cover (above to the power inlet) with a flat blade screwdriver

•remove the fuse from the holder and replace it with the appropriate type.

• reinstall the fuse holder

Always replace the fuse with one of the exact same specifications.

Ten:

For systems operating at 115 volts, use only a 5x20 mm, T3A, 250-volt slow-blow fuse.

For systems operating at 230 volts, use only a 5x20 mm, T2.0A, 250-volt slow-blow fuse.

Twelve:

For systems operating at 115 volts, use only a 5x20 mm, T5A, 250-volt slow-blow fuse.

For systems operating at 230 volts, use only a 5x20 mm, T2.5A, 250-volt slow-blow fuse.

Troubleshooting

If the Ten or Twelve fails to operate at all when the Power Switch is turned on, thoroughly check the power cord, input and output connections

If the Ten or Twelve turns on but the LED indicator fails to illuminate, mis-wiring or a power surge may have caused the protection fuse to blow. Replace it with one of correct type and value.

If the Ten or Twelve turns on but its status LED stays red, the unit is gone into protect mode, which could be caused by incorrect wiring, short circuits, or excessive volume. Turn off the Power Switch on the subwoofer for two or more seconds to reset, and double check all speaker cables to be sure that no small metal strands are shorting the terminals.

If the Ten or Twelve subwoofer has a loud hum when you turn it on. The following is what you can I do to get rid of the hum;

The DSS system and all cable TV systems have a ground wire connected to the shield of the signal on the outside of the house and driven into the earth with a metal rod or water pipe. The Ten and Twelve is ground- ed to the power outlet through the third prong of the power cord. The AC wiring in the building has the ground conductor connected to a metal rod or water pipe outside the building. Once a patch cord is connected between the DSS system and the subwoofer, a complete circuit is formed called a ground loop. Current flowing in the ground loop can cause very large amounts of noise in the system.