background image

8

Rear Panel Connections and Switches

1�  Input Mode

 

To select the BALANCED or UNBALANCED 

connection, use the INPUT MODE switch 

to toggle between these two options. Each 

input section can accept a male balanced XLR 

cable or a male unbalanced RCA cable. All 

inputs must use the same type of connection 

(BALANCED or UNBALANCED). Refer to 

page 5, 

Connector Information

2� 

Amplifier Mode

 

MONO is the common choice for most  

applications of the MC451. The signal from 

a single preamplifier will be sent to both the 

solid state and vacuum tube amplifiers with the 

frequency range tailored by the crossover to 

match the attached loudspeaker. 

SEPARATE

 can be useful for situations where 

an external crossover is used. SEPARATE can 

also be used for feeding full-range signals to 

two separate loudspeakers from a single MC451. 

Note: If you need to switch the INPUT or AMPLIFIER 

MODE, it is best to do so when the MC451 is 

powered off to avoid any unpleasant noise from the 

loudspeakers.

 

3�  Vacuum Tube Input

  

With the 

AMPLIFIER MODE

 switch set to 

MONO, the input is disabled. 

With the 

AMPLIFIER MODE

 switch set to 

SEPARATE

, this input sends a full range input 

signal to the vacuum tube amplifier. 

4�  Mono / Solid State Input

 

With the 

AMPLIFIER MODE

 switch set to 

MONO, the input signal is sent to the internal 

crossover. The crossover then sends signals to 

each amplifier section based on the crossover 

settings.  

With the 

AMPLIFIER MODE

 switch set to 

SEPARATE

, this input sends a full range input 

signal to the solid state amplifier. 

5�  Crossover

 

Refer to page 12, 

Setting Up the Crossover 

for 

additional information. 

6�  Power Control  

Power control allows the MC451 to send and 

receive control signals when connected to other 

McIntosh products. In this way, powering on 

or powering off a single component can do the 

same for multiple units. 

POWER CONTROL IN accepts an On/Off 

signal from +5 to +12 volts. Meter and tube 

lights can be controlled as well.  

POWER CONTROL OUT will provide a +12 

volt signal with a total current up to 25 mA. 

Connections are made using an 1/8 inch stereo 

mini phone plug. Refer to page 5, 

Connector 

Information

7� 

Auto Off Function

 

The MC451 incorporates power saving circuitry 

to automatically activate the power saving 

standby mode. The MC451 will turn off after 

approximately 30 minutes of no audio signal in 

both amplifiers when the AUTO OFF switch is 

set to ENABLED. 

If the AUTO OFF switch is set to DISABLED, 

the MC451 will remain on regardless of the 

presence of any audio signal. 

When there is a power control connection 

between the MC451 and a preamplifier or source 

component, the AUTO OFF function is disabled 

regardless of switch position.

8�  Vacuum Tube Outputs

 

Refer to page 5, 

Connecting a Loudspeaker

  

for additional information. 

9�  Solid State Outputs

 

Refer to page 5, 

Connecting a Loudspeaker

  

for additional information. 

10� AC Input

  

Connect the MC451 power cord to a live AC 

outlet. Refer to the rear panel for voltage and 

current requirements. 

11� Fuse

 

Under normal operating conditions the fuse 

should not need to be replaced. If required, refer 

to the rear panel for proper fuse type. 

Содержание MC451

Страница 1: ...McIntosh Laboratory Inc 2 Chambers Street Binghamton New York 13903 2699 Phone 607 723 3512 www mcintoshlabs com MC451 Dual Mono Power Amplifier Owner s Manual...

Страница 2: ...al Specifications 14 Packing Instructions 15 Packaging Parts List 15 Thank You from All of Us at McIntosh You have invested in a precision instrument that will provide you with many years of enjoyment...

Страница 3: ...ir Warm Air Dimensions The following dimensions can assist in determining the best location for your MC451 17 8 45 4 cm 10 8 27 6 cm 11 16 30 cm 12 4 31 1 cm WATTS HOLD LIGHTS OFF METER REMOTE OFF ON...

Страница 4: ...porarily remove the tube cover To remove the tube cover 1 Use a 2 phillips head screw driver to remove the four screws two on each side that hold the tube cover 2 Pull the tube cover upward from the c...

Страница 5: ...nnection It is a safe bet to use the lower impedance output terminals for a speaker whose impedance falls between two choices Loudspeaker Cables When connecting loudspeakers to the MC451 it is very im...

Страница 6: ...too high a circuit in Power Guard SGS is activated which then dynamically attenuates the input signal in real time to keep the vacuum tubes operating at safe levels 5 POWER GUARD LED Indicates when P...

Страница 7: ...7 Front Panel Displays and Knobs...

Страница 8: ...ut sends a full range input signal to the solid state amplifier 5 Crossover Refer to page 12 Setting Up the Crossover for additional information 6 Power Control Power control allows the MC451 to send...

Страница 9: ...2 SOLID STATE 300W OUTPUTS CLASS 2 WIRING VACUUM TUBE 150W OUTPUTS CLASS 2 WIRING POWER CONTROL OUT IN AUTO OFF ENABLED DISABLED CROSSOVER MONO MODE VACUUM TUBE INPUT INPUT MODE BALANCED UNBALANCED BA...

Страница 10: ...R POINT Hz 1 2 3 3 6 0 VACUUM TUBE LEVEL dB HDMI ARC DA2 DIGITAL AUDIO MODULE USB AUDIO COAX 2 COAX 1 MCT OPTICAL 2 OPTICAL 1 DIGITAL AUDIO INPUTS SERIAL NUMBER POWER CONTROL MAIN TRIG 1 TRIG 3 PASSTH...

Страница 11: ...CONTROL OUT IN AUTO OFF ENABLED DISABLED CROSSOVER MONO MODE VACUUM TUBE INPUT INPUT MODE BALANCED UNBALANCED BAL UNBAL MONO SOLID STATE INPUT AMPLIFIER MODE MONO SEPARATE BAL UNBAL 300 250 400 550 1...

Страница 12: ...plifier CROSSOVER MONO MODE 300 250 400 550 180 130 800 1k 100 CROSSOVER POINT Hz 1 2 3 3 6 0 VACUUM TUBE LEVEL dB The VACUUM TUBE LEVEL knob allows gain adjustments to be made to the vacuum tube ampl...

Страница 13: ...er point and 0dB level difference Other crossover points will have similar curves 6 4 2 0 2 4 6 8 10 12 14 16 18 20 22 24 26 20 30 50 100 200 300 500 1k 2k 3k 5k 10k 20k Frequency Hz Decibels Combined...

Страница 14: ...from 20Hz to 20 000Hz 0 3 0dB from 10Hz to 100 000Hz Total Harmonic Distortion 0 005 maximum harmonic distortion at any power level from 250 milliwatts to rated power 20Hz to 20 000Hz Intermodulation...

Страница 15: ...n the bottom pad Failure to do this will result in shipping damage Use the original shipping carton and interior parts only if they are all in good serviceable condition If a shipping carton or any of...

Страница 16: ...cts is the policy of McIntosh Laboratory Incorporated who reserve the right to improve design without notice Printed in the U S A McIntosh Laboratory Inc 2 Chambers Street Binghamton NY 13903 www mcin...

Отзывы: