Figure 4.2 Rear Panel Connectors and Controls; 4 Operation; 4.2.2 Rear Panel Facilities- Page 12

Micro-Tech Series 

Power Amplifiers

page 12

Operation Manual

4.2.2  Rear Panel Facilities

F. Power Cord

All units are shipped with an approprate plug and 
cord for the required AC voltage.

G. Stereo/Mono Modes Switch

•

Use Stereo mode for normal two-channel oper-

ation.

•

Use Bridge-Mono mode to drive a single chan-

nel with a load impedance of at least 4 ohms.

•

Use Parallel-Mono mode to drive a single 

channel with a load impedance less than 4 
ohms.

Important: Turn off the amplifier before changing the 
Stereo/Mono modes switch.

H. Reset Switches (Micro-Tech 2400 only)

The Micro-Tech 2400 has two push-button reset 
swiches on the back panel that are used to reset the 
circuit breakers for the high-voltage power supplies. 
Refer to Section 5.1.5 in the rare event of a tripped 
breaker.

I. MT-XLR Module

This module provides two balanced XLR inputs.  
Because the MT-XLR connectors are in parallel with 
the amplifier’s built-in phone connectors, an input 
signal fed to either input can be fed to another 
amplifier from the unused connector for that chan-
nel. If you prefer to use barrier block inputs instead, 
order the MT-BB accessory  (see Section 5.2). 

Input Sensitivity Switch

The three-position input sensitivity switch (Figure 
4.2) is located inside the amplifier behind the MT-
XLR module (I). See Section 3.7 for details.

J. Level Controls

Used to set the amplifier's output levels. These con-
trols are on the back panel to prevent tampering. Be 
sure to turn down the Channel-2 level control (fully 
counterclockwise) when operating in Bridge-Mono 
or Parallel-Mono mode.

K. Balanced Phone Jack Inputs

A balanced ¼-inch phone jack input is provided for 
each channel. The jacks may be used with either 

balanced (tip, ring and sleeve) or unbalanced (tip 
and sleeve) lines (refer to Figure 3.5). Balanced XLR 
ijnputs for each channel are provided with the 
MT-XLR module. Barrier-block input connectors are 
available with the MT-BB accessory (see Section 
5.2.2). Caution: Do not use the Channel-2 input in 
either mono mode.

L. Ground Lift Switch

Used to isolate the phone jack signal grounds from 
the AC power (chassis) ground. Moving the switch 
to the "lift" position helps prevent the hum associ-
ated with ground loops. Sliding the switch to the left 
isolates or "lifts" the grounds by placing an imped-
ance between the sleeve of each phone jack and the 
AC ground.

M. Output Jacks

A pair of versatile binding posts is provided for out-
put connection to each channel. Loudspeakers can 
be easily connected using banana plugs, spade lugs 
or bare wire (European models do not accept 
banana plugs). See Section 3.5.

CAUTION:
THIS COVER IS NECESSARY FOR
EFFICIENT COOLING OF THE AMPLIFIER.
REMOVE ONLY TO ACCESS GAIN SWITCH.

0

1

2

3

4

5

6

7

8

9

10

11

12

0

1

2

3

4

5

6

7

8

9

10

11

12

BRIDGE-MONO WIRING

TURN AMPLIFIER OFF.

SET STEREO/MONO
SWITCH TO
BRIDGE-MONO.

OUTPUT ACROSS
RED TERMINALS
ONLY. (CH-1
IS POSITIVE.)

PARALLEL-MONO WIRING

TURN AMPLIFIER OFF.

SET STEREO/MONO
SWITCH TO
PARALLEL-MONO.

ADD JUMPER (14
GAGE OR LARGER)
ACROSS RED
TERMINALS.

OUTPUT ACROSS CH-1
TERMINALS ONLY.

1

2

3

4

1

2

3

CH-2

CH-1

+

–

–

+

INPUT GROUND LIFT

(AFFECTS PHONE INPUTS ONLY.)

CAUTION: TURN OFF AMPLIFIER

 BEFORE CHANGING THIS SWITCH!

STEREO

BRIDGE

MONO

PARALLEL

MONO

CLASS 1
OUTPUT

WIRING

REQUIRED.

WARNING: 

TO REDUCE THE RISK OF FIRE OR

ELECTRIC SHOCK DO NOT EXPOSE THIS EQUIPMENT
TO RAIN OR MOISTURE.

OUTPUTS

LIFT

REG. U.S. PAT. OFF.

4,330,809
4,611,180

MODEL:  MICRO-TECH 2400 SERIES
      AC VOLTS: 120    AMPS: 17   60 Hz

MAXIMUM OUTPUT:  900 WATTS
PER CHANNEL INTO 2 OHMS AT 1 KHz
WITH NO MORE THAN 0.1% THD.

UNBALANCED

INPUT WIRING

BALANCED

INPUT WIRING

+

–

TIP

RING

SLEEVE

GND

+

TIP

SLEEVE

GND

CH-2

(MONO)

INPUT

GAIN

CH-1

INPUT

GAIN

THIS AMPLIFIER IS EQUIPPED WITH SELECTABLE INPUT SENSITIVITY. REMOVE COVER PLATE (ABOVE) TO ACCESS SENSITIVITY SWITCH.

®

INTERNATIONAL, INC.

ELECTRONIC EQUIPMENT

ELKHART, IN 46517
MADE IN U.S.A.

SERIAL NUMBER

0000

000000

F

G

H

K

K

L

M

M

J

J

PUSH TO RESET

I

Figure 4.2 Rear Panel Connectors and Controls

4 Operation