6
CHAPTER 2
NOTE:
Refer to Appendix B for details on
the 700-HP subwoofer’s AC voltage require-
ments.
After applying AC power, the proper operating voltage is
automatically selected, but the system is muted. During the
next three seconds the following events occur:
1. The primary fans turn on.
2. The main power supply slowly ramps on.
3. The green Active LED on the user panel lights up,
indicating that the system is enabled and ready to pass
audio signals.
CAUTION:
If the Active LED does not il-
luminate or the system does not respond to
audio input after ten seconds, remove AC power im-
mediately. Verify that the voltage is within the proper
range. If the problem persists, please contact Meyer
Sound or an authorized service center.
If voltage drops below the lower boundary of either safe
operating range (brownout), the 700-HP subwoofer uses
stored energy to continue functioning briefly, and shuts
down only if voltage does not rise above the lower bound-
ary before the 700-HP subwoofer’s storage circuits are
depleted. How long the 700-HP subwoofer will continue to
function during brownout depends on the amount of volt-
age drop and the audio source level during the drop.
If the voltage increases above the upper boundary of either
range, the power supply rapidly turns off, preventing dam-
age to the unit.
NOTE:
If voltage fluctuates within either
operating range, automatic tap selection
stabilizes the internal operating voltage. This tap
selection is instantaneous, and there are no audible
artifacts.
If the 700-HP subwoofer shuts down due to either low or
high voltage, its power supply automatically turns on again
after three seconds if the voltage has returned to either nor-
mal operating window. If the 700-HP subwoofer does not
turn back on after ten seconds, remove AC power immedi-
ately (see previous Caution).
NOTE:
It is recommended that the supply
be operated in the rated voltage windows at
least a few volts away from the turn on/off points.
This ensures that AC voltage variations from the ser-
vice entry – or peak voltage drops due to cable runs
– do not cause the amplifier to cycle on and off.
CURRENT REQUIREMENTS
The 700-HP subwoofer presents a dynamic load to the AC
mains, which causes the amount of current to fluctuate
between quiet and loud operating levels. Since different
cables and circuit breakers heat up at varying rates, it is es-
sential to understand the types of current ratings and how
they correspond to circuit breaker and cable specifications.
The
maximum long-term continuous current
is the maxi-
mum rms current during a period of at least ten seconds.
It is used to calculate the temperature increase in cables,
in order to select a cable size and gauge that conforms to
electrical code standards. It is also used to select the rating
for slow-reacting thermal breakers.
The
burst current
is the maximum rms current during a
period of approximately one second, used to select the
rating of most magnetic breakers and to calculate the peak
voltage drop in long AC cables according to the formula:
V pk (drop) = I pk x R (cable total)
The
ultimate short-term peak current
is used to select the
rating of fast-reacting magnetic breakers.
Use Table 2.1 below as a guide when selecting cable gauge
size and circuit breaker ratings for your operating voltage.
Table 2.1. Current Ratings for the 700-HP Subwoofer
Current Draw
115 V AC
230 V AC
100 V AC
Idle current
0.640 A rms
0.320 A rms
0.850 A rms
Max. long-term
continuous
8.8 A rms
4 A rms
10 A rms
Burst current
19 A rms
9.5 A rms
22 A rms
Ultimate short-
term peak
39 A pk
20 A pk
45 A pk
NOTE:
For best performance, the AC cable
voltage drop should not exceed 10 volts, or
10 percent at 115 volts and 5 percent at 230 volts.
Make sure that even with the AC voltage drop the
AC voltage always stays in the operating windows.
