ETI Sound Systems, INC US-4000 Manuel D’Utilisation

THE BEAUTY OF POWER

NOTe: Match the pin designations printed next  

 

to the output connectors on rear panel to ensure  

 

proper connections.

The circuit breaker protects the amplifier from faults 

at the AC supply and serves as protection when the

amplifier fails.

If the circuit breaker trips, cutting AC power

supply to your amplifier, it may indicate a serious 

malfunction or failure. Wait for the circuit breaker to 

cool before resetting it by simply pressing the reset 

knob. If the circuit breaker repeatedly trips, especially 

when there is no signal on the inputs or outputs, this 

indicates a failure of your amplifier. DISCONNECT

the power cord from the amplifier immediately and 

contact an authorized B-52 Service Center.  

There are rare instances when the circuit breaker acts 

on a constant heavy overload with a very low imped-

ance load connected to amplifier, protecting your 

amplifier against such improper usage. In such cases 

you need to check and correct your load (loudspeak-

ers) to provide for the proper load impedance,  

and/or reduce output signal.

IEC connector for the AC power cable. Connect the

supplied heavy-gauge 3-pin IEC power cable.

NOTe: Never disconnect the EARTH pin from the  

AC connection. It will defeat safety measures  

 

used in your power amplifier and void the  

 

warranty.

US-Series amplifiers feature comprehensive protection 

circuitry that protects both the loudspeakers and the 

electronics from malfunctioning. The protection is non-

intrusive, sonically transparent and does not affect the 

sound unless there are extreme conditions that acti-

vate the protection circuitry.

The PROTECT LEDs on the front panel illuminate when

the protection is active during the power-up sequence, 

when thermal protection is activated, or when there is 

a malfunction. When the PROTECT LEDs are ON, the

amplifier’s outputs are muted.

INITIAl POWeR-UP: The protection circuitry will 

activate for about two to three seconds from the time 

you turn ON the amplifier. The speaker outputs are

muted during this period. If the amplifier is operating 

normally, the protection circuitry will deactivate and 

the amplifier will switch to operation mode.

NOTe: It is normal for the PROTECT LED to fade  

gradually after the amplifier is turned OFF.

TheRMAl PROTeCTION: Excessive heat-sink tem-

peratures will engage the thermal protection circuitry 

to avoid damage to your amplifier. The speaker 

output will mute and the PROTECT LED will illuminate.

Thermal protection only engages on the channel  

which has the overheating heatsink, except the US-

1200 where both channels will be muted. The thermal 

protection will automatically restore to normal opera-

tion mode automatically once the heatsink tempera-

ture drops to a safe level.

NOTe: If the thermal protection constantly  

 

activates, check the impedance of your loud- 

 

speakers and the condition of the air filters on  

 

front of the amplifier. The loudspeakers  

 

impedance must not be lower than what is  

 

specified in this manual for 2-channel and  

BRIDGE operation. 8 Ohms and 4 Ohms speaker  

loads per channel (8 Ohms and 16 Ohms in  

BRIDGE mode) should not trigger the thermal  

 

protection circuitry if the air access is not  

blocked and the air filters are clean. 2 Ohms  

speaker loads per channel (4 Ohms in BRIDGE  

 

mode) can cause the thermal protection circuitry  

 

to activate occasionally. If this occurs, decrease  

 

the signal level and consider reconthe speakers  

 

connections to reduce the load on the amplifier  

(for example, do not connect too many speakers  

 

in parallel to the same channel).

NOTe: Make sure there is adequate air access