Tapco S8 manual Overexcursion Protection, Thermal Protection, Integrated Magnetic Shielding

Protection Circuits

There are several protection mechanisms designed into the S•8 to safeguard the loudspeakers and amplifi ers 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 Clip LED indications,

excessive distortion), you can still damage the speakers in the S•8 by overdriving them past the point of amplifi er clipping. Such damage is beyond the scope of the warranty.

Overexcursion Protection

A 12 dB/octave high-pass fi lter at 40 Hz just prior to the low-frequency amplifi er prevents very low frequencies from being amplifi ed. 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 amplifi ers produce heat. The S•8 is designed to be effi cient both electrically and thermally.

•If for some reason the heatsink gets too hot, a thermal switch activates and turns off the amplifi er. This protection operates independently for the low-frequency and high-frequency amplifi ers. Therefore, it is possible for only the low frequency or high frequency amplifi er 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 airfl ow 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 airfl ow through the fi ns.

Integrated Magnetic Shielding

The S•8 contains drivers with large magnetic structures. The drivers’ magnets are shielded to help prevent the magnetic fi eld from radiating out into the environment and playing havoc with computer monitors or TV screens. Unshielded speakers can cause distortion in both the shape and color of the picture if placed too close to a CRT (cathode ray tube). If you have a particularly sensitive computer monitor or TV screen, it may be necessary to move the speakers a few inches away.

Input Signal Wiring

You should use high-quality, shielded cable to connect the signal source to the INPUT jack on the S•8.

•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.

•In certain home theater applications, it may be necessary to connect the speaker outputs from a stereo receiver to the inputs of the S•8s, if the receiver doesn’t have preamp outputs or other line-level output connections.

CAUTION: Do not attempt to connect a speaker output directly to the input of the S•8! Speaker levels are much higher than line levels and can damage the input circuitry in the S•8.

You can, however, insert a speaker-level-to- line-level signal attenuator between the receiver’s speaker output and the S•8’s input. Your Mackie dealer may be able to help you fi nd one, or if you enjoy do-it-yourself projects, you can build your own. Contact our tech support department for more information.

10