Baldwin Boxall M2420 Operating instructions

Brand: Baldwin Boxall

Model: M2420

Category: Musical Equipment

Type: Operating instructions

Baldwin Boxall Communications Ltd.

Wealden Industrial Estate, Farningham Road

Crowborough, East Sussex, TN6 2JR

Telephone: 01892 664422 Fax: 01892 663146

Website: www.baldwinboxall.co.uk

Email: mail@baldwinboxall.co.uk

IM2420

Issue 1 03/08/1999

M2420 Amplifier

Operating Instructions

- 2 - Issue 1

Mitre 2420

The Mitre 2420 is equipped with two 0 dBM balanced line inputs per channel which incorporates a

priority switching system. The priority is selected using a two-way dual in line switch. Switch ‘1’

when selected ‘on’ provides input 2 muting when 1 is accessed. Switch ‘2’ when selected ‘off’

enables the first input irrespective of access conditions. When both switches are selected ‘on’ input 1

will override input 2. Therefore it is possible to have both inputs mixing together or cascade priority

depending on the requirements, refer to rear panel drawing.

Input 1 pre-set volume controls are located on the rear and input 2 are on the front panel.

A 200 Hz 12 dB/octave high bass filter may be selected to limit the bass response of any channel.

This is useful if the speakers used have a limited response i.e. horn types.

The output stages are protected against overload and high temperature conditions. If the temperature

exceeds a safe level the output signal is reduced to a low level preventing permanent damage to the

amplifier. When it cools down, it will perform as normal without manual resetting.

The inputs to each amplifier are presented on two separate four-way plug-in terminal connectors, each

connector provides a balanced audio input, ground and access DC control input. The output is

presented on a three-way plug/screw termination connector providing 50V or 100V output.

- 3 - Issue 1

Mitre 2420 Technical Specification

Rated output power

100V line 230V AC supply 4 x 20W - 500 Ohms

THD 1 kHz rated output from all channels

230V AC supply Less than 0.5% typically 0.2%

Typical output power 1% THD

230V AC supply 4 x 25W - 400 Ohms

Output regulation

1 kHz 100V line Better than 1.4 dB

Output voltages obtainable by pin selection 50 & 100V

Supply voltage AC 230V 50-60 Hz

Power consumption @ 230V

Quiescent

Rated output power @ 1 kHz 12VA

180VA

Fuse protection

1 x AC supply 20 x 5 mm

8 x DC (amplifier) auto blade type

1 x DC Aux output 20 x 5 mm

2A(T)

3A(F)

2A(T)

Input type per channel 2 x line balanced with priority gating

Input sensitivity 0.5V @ 40K Ohms balanced

Input common mode rejection ratio

50 Hz - 30 kHz

Frequency response -3dB @

Signal to noise ratio

Selectable high pass filter

Better than 40 dB typically 60 dB

80 Hz - 20 kHz

Better than 85 dB

200 Hz 12 dB/octave

Channel separation @ 1 kHz Better than 60 dB

High pass filter 200 Hz - 12 dB/octave

DC Aux output 30V @ 1.5A max.

Terminations

1 x AC supply input

8 x Line signal inputs

1 x DC Aux output

4 x Loudspeaker line output

3-pin

4-pin

2-pin

3-pin

DIN IEC 6A

Screw terminated connector

Crimp terminated connector

Screw terminated connector

Dimensions (mm) (D x W x H) 340 x 430 x 90

Weight 8Kg

- 4 - Issue 1

40W20W

P17 = CHANNELS 1&2

P18 = CHANNELS 3&4

CHANGE LINK FROM 20W TO 40W

PART VIEW OF PRINTED CIRCUIT

BOARD WITH COVER REMOVED

100V

0V50V

50V

LOUDSPEAKER

100V

0V50V

50V

LOUDSPEAKER

100V

OUTPUT CH1

OUTPUT CH2

CHANNEL 1

CHANNEL 2

40W 250 ohms

CHANNEL 1&2 OR 3&4 OUTPUTS

PART VIEW OF REAR PANEL

100V

0V50V

50V

LOUDSPEAKER

100V

0V50V

50V

LOUDSPEAKER

100V

0V50V

50V

LOUDSPEAKER

100V

0V50V

50V

LOUDSPEAKER

100V

ACCESS

INPUT

BALANCED

0VACCESS

INPUT

BALANCED

OUTPUT CH1

OUTPUT CH2

OUTPUT CH3

OUTPUT CH4

CH1-1

CH1-2

CHANNEL 1

OFF

OFFON

INPUT PRIORITY SWITCHING

INPUT1 AND 2 WILL MIX WHEN THEY ARE ACCESSED.

INPUT1 WHEN ACCESSED OVERRIDES INPUT2.

INPUT1 ENABLED IRRESPECTIVE OF ACCESS STATE. INPUT2 WILL MIX WHEN ACCESSED.

INPUT1 ENABLED IRRESPECTIVE OF ACCESS STATE. INPUT1 ACCESS WILL OVERRIDE 2

OFF

0VACCESS

INPUT

BALANCED

ACCESS

INPUT

BALANCED

ACCESS

INPUT

BALANCED

ACCESS

INPUT

BALANCED

ACCESS

INPUT

BALANCED

ACCESS

INPUT

BALANCED

CHANNEL 4CHANNEL 3CHANNEL 2

100V OR 50V LOUDSPEAKER OUTPUT

CHANNEL 1

CHANNEL 2

CHANNEL 3

CHANNEL 4AUX 24V DC OUTPUT 1.5A MAX

TO FEED BVMX ETC. FUSED AT T2A

NOTE. INPUT 2 VOLUME CONTROL IS MOUNTED ON FRONT PANEL

BALANCED SIGNAL INPUT

500mV @ 44Kohms

ACCESS CLOSE TO 0V TO

ACCESS INPUT

CH2-1

CH2-2

CH3-1

CH3-2

CH4-1

CH4-2

CH4 I/P1 VOLUMECH3 I/P1 VOLUMECH2 I/P1 VOLUMECH1 I/P1 VOLUME

FIG 1: M2420 REAR PANEL VIEW

CUT FOR 200Hz

HP FILTERCUT FOR 200Hz

HP FILTER

40W20W

CHANNEL 1CHANNEL 4

CHANNEL 3

CHANNEL 2

REMOVE LINK TO ENABLE

200Hz 12dB/OCT FILTERREMOVE LINK TO ENABLE

200Hz 12dB/OCT FILTER

200Hz HIGH PASS FILTER

PART VIEW OF PRINTED CIRCUIT

BOARD WITH COVER REMOVED

- 5 - Issue 1

PSU

24V AUX SUPPLY

OUTPUT 1.5A MAX

+VE

-VE

MAINS

SWITCH MAINS

FUSE

230V AC

50Hz-60Hz

+30V

-30V

T2A

MITRE 2420

BLOCK DIAGRAM

LK1

ENABLE FILTER

REMOVE LINK TO

PRIORITY

LOGIC

200Hz HIGH

PASS FILTER

POWER

AMPLIFIER

100V

50V

F3A

+30V

-30V

CHANNEL 1

VOLUME

INPUT 2

I/P

BALANCED

INPUT 500mV

INPUT 2

ACCESS

FRONT

BALANCED

INPUT 500mV

I/P 1 VOLUME

INPUT 1

I/P

ACCESS

INPUT 1

REAR

LK1

ENABLE FILTER

REMOVE LINK TO

200Hz HIGH

PASS FILTER

POWER

AMPLIFIER

100V

50V

F3A

+30V

-30V

20W

40W

PRIORITY

LOGIC

VOLUME

INPUT 2

I/P

BALANCED

INPUT 500mV

INPUT 2

ACCESS

FRONT

BALANCED

INPUT 500mV

I/P 1 VOLUME

INPUT 1

I/P

ACCESS

INPUT 1

REAR

CHANNEL 2

LK1

ENABLE FILTER

REMOVE LINK TO

PRIORITY

LOGIC

200Hz HIGH

PASS FILTER

POWER

AMPLIFIER

100V

50V

F3A

+30V

-30V

VOLUME

INPUT 2

I/P

BALANCED

INPUT 500mV

INPUT 2

ACCESS

FRONT

BALANCED

INPUT 500mV

I/P 1 VOLUME

INPUT 1

I/P

ACCESS

INPUT 1

REAR

LK1

ENABLE FILTER

REMOVE LINK TO

200Hz HIGH

PASS FILTER

POWER

AMPLIFIER

100V

50V

F3A

+30V

-30V

20W

40W

PRIORITY

LOGIC

VOLUME

INPUT 2

I/P

BALANCED

INPUT 500mV

INPUT 2

ACCESS

FRONT

BALANCED

INPUT 500mV

I/P 1 VOLUME

INPUT 1

I/P

ACCESS

INPUT 1

REAR

CHANNEL 3

CHANNEL 4

20W

P17

P18

Baldwin Boxall M2420 Operating instructions

Brand: Baldwin Boxall

Model: M2420

Category: Musical Equipment

Type: Operating instructions

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Baldwin Boxall M2420 Operating instructions

Baldwin Boxall M2420 Operating instructions

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