GENERAL PRECAUTIONS

RACK MOUNTING

The M•800 amp requires two rack space

units (2U = 3.5"). It also requires 16.25" depth inside the rack, including the rear supports. When designing your rack, put the heavier items at the bottom and the lighter items toward the top.

Secure the front panel of the amplifier to the front of the rack using four screws with soft washers to prevent scratching the panel. In ad- dition, because of the weight of the amplifier, you must secure the rear support brackets of the amplifier to the back of the rack. You could use a support rail or shelf across the back of the rack, or angle brackets attached between the rear support brackets and the rear rails of the rack. This is recommended for all components mounted in a rack that is going to be moved frequently .

THERMAL CONSIDERATIONS

The M•800 amp is fan-cooled and brings air in through the front and out through the sides. Make sure that cool air is available at the front of the amplifier, and that there is room on each side for the warm air to exit from the amplifier and dissipate. If rack-mounted, make sure there is room for the warm air to circulate around the side and out through the rear of the rack. In a typical rack, there will be a space of 1 to 2 inches on either side of the amplifier. This is adequate to allow the warm air to exit from the amplifier.

AC POWER CONSIDERATIONS

Be sure the M•800 is plugged into an outlet that is able to supply the correct voltage specified for your model. If the voltage should drop below 97% of line voltage, the M•800 will no longer be able to supply rated power. (It will continue to operate down to 65% of the rated voltage, but it won’t be able to reach full rated power). The amplifier will mute if the voltage drops below 65% of the rated voltage. This could happen if you use a long extension cord, reproducing music with large peaks.

Be sure the AC outlet can supply enough current to allow full power operation of all the amplifiers plugged into it. The outlet should be a three-prong socket that matches the power cord.

WARNING: Bypassing the plug’s ground pin can be dan- gerous. NEVER do it!

The AC current demand of an amplifier varies depending on several factors, including the crest factor and the duty cycle of the program material. Under typical conditions reproducing rock music where musical peaks are just below clipping, the M•800 requires the following average currents (@120VAC, 60 Hz):

 

Average

Peak

 

Current

Current

Amplifier Loading

Required

Required

2 ohms per side or 4 ohms bridged

7 A

16 A

4 ohms per side or 8 ohms bridged

4.5 A

11 A

8 ohms per side or 16 ohms bridged

3 A

6.5 A

It is recommended that a stiff supply of AC power be used because the amplifier places high current demands on the AC line. The more power that is available on the line, the louder the amplifier will play and the more peak output power will be available for cleaner, punchier bass.

Under typical conditions, reproducing rock music where musical peaks are just below the clipping point, you can safely connect more than one amplifier to a 15A service as shown:

 

Maximum Number

 

of Amplifiers

Amplifier Loading

on a 15A Service

2 ohms per side or 4 ohms bridged

2

4 ohms per side or 8 ohms bridged

3

8 ohms per side or 16 ohms bridged

4

 

 

Due to in-rush current, however, you should avoid turning them all on at the same time. Rather, sequence them on, one at a time, to prevent popping the circuit breaker.

The extension cord used to supply power to the “amp rack” should have a third wire safety ground to avoid presenting a safety hazard. We also recommend using a cord that has conductors large enough to avoid severely limiting the amplifier’s ability to supply high currents on transients. With this in mind, we recommend using the following for a fully loaded 15A service:

Extension Cord Length

Wire Gauge

25 feet

14 AWG

50 feet

12 AWG

100 feet

10 AWG

18