Meyer Sound 100 ユーザーズマニュアル

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All components in an audio system (self-powered loud-
speakers, processors, etc.) must be properly connected to 
an AC power distribution system, to ensure that AC line 
polarity is preserved and that all grounding points are con-
nected to a single node or common point using the same 
cable gauge as the neutral and line cables.

Improper grounding of connections 

between loudspeakers and the rest of the 

audio system may produce noise or hum, or cause 
serious damage to the input and output stages of the 
system’s electronic components.

Before applying AC power to any 

Meyer Sound self-powered loudspeaker, make 

sure that the voltage potential difference between the 
neutral and earth-ground lines is less than 5 V AC.

Figure 1 illustrates a basic three-phase AC distribution sys-
tem with the loudspeaker load distributed across the three 
phases. All loudspeakers are connected to common neutral 
and earth-ground lines.

The Acheron operates safely and continuously when the AC 
voltage stays within 85–134 V  AC and 165–264 V  AC at 50 
or 60 Hz. The loudspeaker allows any combination of volt-
age to GND (neutral-line-ground or line-line-ground).

If the voltage drops below 85 V (brownout), the Acheron 
uses stored power to continue operating temporarily; the 
loudspeaker will shut down if the voltage does not rise 
above the low boundary before the stored power is used.

If the voltage rises above 275 V, the power supply could 
become damaged.

The power source for the Acheron 

should always operate within the required volt-

age range, at least a few volts from the upper and 
lower ranges. This ensures that AC voltage variations 
from the service entry — or peak voltage drops due 
to cable runs — will not cause the loudspeaker’s 
amplifier to cycle on and off or cause damage to the 
power supply.

Since the Acheron does not require a dedi-

cated neutral line, and it can tolerate elevated 

voltages from the ground line, it can be connected to 
line-line terminals in 120 V, 3-phase Wye systems. 
This results in 208 V AC between lines (nominal) and 
therefore draws less current than when using 120 V 
AC (line-neutral). Make sure that the voltage remains 
within the Acheron’s recommended operating win-
dows (85–134 V AC and 165–264 V AC). The ground 
line must always be used for safety reasons and the 
line-to-ground voltage should never exceed 250 V AC 
(typically 120 V AC from line-to-ground).

The current draw for the Acheron is dynamic and fluctuates 
as operating levels change. Since different cables and cir-
cuit breakers heat up at varying rates, it is important to 
understand the following types of current ratings and how 
they affect circuit breaker and cable specifications.

■

Idle Current — The maximum rms current during idle 
periods.

■

Maximum Long-Term Continuous Current — The 
maximum rms current during a period of at least 10 sec-
onds. The Maximum Long-Term Continuous Current is 
used to calculate temperature increases for cables, to 
ensure that cable sizes and gauges conform to electrical 
code standards. The current rating is also used as a rat-
ing for slow-reacting thermal breakers.