MB QUART Reference Amps: RAB 450 4-Channel AmplifierAMPLIFIER FEATURE DESCRIPTION

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RAB 450 4-Channel Amplifier AMPLIFIER FEATURE DESCRIPTION

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1  LED INDICATORS

1. POWER: Lights up when power and remote turn-on is 

applied.

2. DIAGNOSTICS: When lit, will indicate a fault condition.

2  CH1/2 MODE

1. DUPE CH3/4 routes signal as selected by the amps 3 & 4 

SELECT to the 1 & 2 amplifier pair. Note that in this case, 

channels 1 & 2 level will be set by the LEVEL CH3/4 control 

only, for an exact duplication of the 3 & 4 amplifier pair signal.

2. FR (FULL RANGE) passes the full frequency range from CH1/2 

INPUT to the inter nal amplifiers.

3. HP (HIGH PASS) will send the range of frequencies above the 

point set by the variable HIGH PASS control.

3  CH1/2 HIGH PASS

1. Variable HIGH PASS filter from 50 Hz to 5 kHz.

2. This control is bypassed when CH1/2 is in DUPE 3/4 or  

FR (FULL RANGE) selection.

4   CH1/2 LEVEL

1. Sets CH1/2 input sensitivity to match the output level of the 

radio/CD player.

2. Note that when the amps’ CH1/2 select switch is in the 

DUPE CH3/4 position, the CH1/2 LEVEL control no longer af 

fects CH1/2.

5  CH3/4 MODE

1. MONO is selected when bridging channels 3 & 4.

2. LP/BP (LOW PASS/BANDPASS) will route those frequencies 

above the HIGH PASS setting and below the LOW PASS setting 

to the internal amplifier. In this mode the HIGH PASS acts as a 

SUBSONIC filter.

3. FR/HP (FULL RANGE/HIGH PASS) bypasses the LOW PASS 

setting and the frequencies reproduced are anything to above 

the HIGH PASS setting.

6  3&4 HIGH PASS

1. This high pass filter, variable from 10 Hz to 1 kHz, is per 

manently connected to the input of the amplifier pair.

2. Since it can var y down to 10Hz, at that point it can be re 

garded as full range.

En gl is h

3. Having this per manently connected to the 3 & 4 pair, allows 

us to use it at any time, either as a subsonic, when set from 

20Hz to 40Hz or as the lower or high pass cut off frequency 

control for active bandpass applications, in conjunction with 

the LOW PASS filter when the CH3/4 MODE switch is in the 

LOW PASS setting.

7  LOW PASS

1. Continuously variable low pass filter, 50 Hz to 5 kHz.

2. Signal routing and mode set by CH3/4 MODE and the LOW 

PASS setting.

8  CH3/4 LEVEL

1. Sets CH3/4 input sensitivity to match the output level of the 

radio/CD player.

2. Note that when the amps’ CH1/2 select switch is in the 

DUPE CH3/4 position, the CH1/2 LEVEL control no longer af 

fects CH1/2.

9  INPUT MODE

1. In the 2CH position, all four channels are provided signal 

from the CH1/2 RCA Inputs.

2. In the 4CH position, channels 1/2 receive input from CH1/2 

RCA inputs, and channels 3/4 receive input from CH3/4 RCA 

inputs.

10  OUTPUT

1. This output can drive the input of other amplifiers in a 

system (daisy chain).

2. In 4CH mode: Set switch 9 to 4CH. All 4 channels are mono 

mixed and then fed to both line out RCAs. This provides a 

front/rear mono signal for constant non-faded sub bass to feed 

a sub amp.

3. In 2CH mode: Set switch 9 to 2CH. Only CH 1&2 are mono 

mixed and fed to both line out RCAs.

11  INPUT

1. CH1-4 inputs to the amplifier, from the radio/CD line level 

(RCA) source with a range of 0.2 volts to 6 volts.

2. Use a line converter if the radio/CD player has speaker (high 

level) outputs only

3. Depending on your system layout, follow the input descripti-

ons in section “Amplifier applications” of this manual.