Bogen MT60A MT125B Operating Manual

Page 1

IS]

saw and 125w
Booster Amplifiers

BOGEN®

A DIVISION OF LEAR SIEGLER, INC.

MT60A & MT125B

INSTALLATION

UNPACKING

The amplifier was thoroughly checked before leaving the
factory. Inspect the amplifier and shipping container carefully
for evidence of improper handling during shipment. In case of
damage, make an immediate claim to the dealer or distributor
from whom the unit was purchased. Ifthe amplifier was shipped
to you, notify the carrier without delay and file a claim.

INPUT CONNECTIONS

Keep input leads away from the output leads and AC power
cables. Unless the driving source provides a low-impedance
output. keep the input lead under ten feet in length. Refer to
"Companion Units and Accessories for Bogen preamplifiers
suitable for'use with the amplifier,

TECHNICAL SPECIFICATIONS

MT60A MT] 2513
RATED OUTPUT POWER 60W 125w
TOTAL HARMONIC DISTORTION Less than 2% at rated output 50 to 15,000 Hz
FREQUENCY RESPONSE :2 dB 20 to 20,000 Hz
HUM & NOISE -85 dB below rated output
REGULATION Better than 2 dB no load to full load
INPUT SENSITIVITY 200mV for rated output
INPUT IMPEDANCE

OUTPUT LOADS (Const. Volt.)
OUTPUT LOADS (Spkr. Imp.)

Hi-Z 50K ohm; Lo-Z 500/600 ohm with TL600 xfmr; Bridging 10K ohm with

4, 8, and 16 ohms (See chart for other impedances)

TL 10K xfmr
25V CT, 25V, 70V, 110V

CONTROLS AND INDICATORS Level control. illuminated power switch, speech filters
SEMICONDUCTORS 6 Transistors. 6 Diodes 10 Transistors, 8 Diodes
POWER CONSUMPTION IZOVAC 60Hz, 180 watts (8' Rated IZOVAC 60Hz. 360 watts @ Rated
Output Output
IZOVAC 60Hz, 25 watts GI} Quiescent IZOVAC 60Hz, 45 watts @. Quiescent
(no output) (no output)
48-56 VDC.3 Amp @ Rated 48-56 VDC. 6 Amps 61 Rated
Output Output
48-56 VDC, 350 mA (45' Quiescent 48-56 VDC, 600 mA (1. Quiescent
(no output) (no output)
AC Circuit Breaker
OVERLOAD PROTECTION Thermal Circuit Breaker
Transient Protection Diodes
DIMENSIONS 3.lx8.5"x 14 (8x 2|.5x36 cm) 5.25"x8.5x15(l3x2l.5x38cm)
WEIGHT 18% lbs. (8.40 kg.) 37 lbs. (12.3 kg.)

PRINTED IN US A

905

54-569l-04

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COMPANION UNITS AND ACCESSORIES

Model Description and Inputs

CAM Mixer-Preamplifier. 4 Hi»Z,Lo-Z Bal MIC. l AUX

CXM Mixer-Preamplifier, 4 Hi-Z/Lo-Z MIC. 2 AUX

CSM Studio Mixer. 4 Lo-Z Bal MIC

CTM Mixer-Preamplifier with built-in anti-feedback,
4 Lo/Hi-Z MIC. 2 AUX

CFC 2; 3 Octave Equalizer

RPK-37 Rack Mounting Kit 19" X 7"(48.26cm x 17.78::m;
mounts 2 units)

TL600 Line Input Transformer. plug-in. 500600-ohm
impedance

TLIOK Bridging Input Transformer. plug-in. 10.000~ohm
impedance

High impedance input

The amplifier can be driven to full output from any source
developing 200 mV across one ofthe Hi-Z inputs, Wire a single-
conductor, low-capacity shielded input cable to a standard
phono plug (Cinch ISA. orequivalent) and connect to one ofthe
Hi-Z jacks on the rear of the chassis. Amplifiers may also be
connected in parallel by connecting a patch cord from Hi-Z
input to Hi-Z input of the amplifiers without loss of gain.

Low impedance input

The amplifier will match a low-impedance (500/600 ohm)
source if a Bogen Model TL-600 transformer is installed in
socket XI on the circuit board. Connect a twisted. shielded pair
(Bogen 813-8450, or equiv.) input cable to the BAL INPUT
LOW Z terminal strip on the rear of the unit. Use the two
outside terminals on the strip for input and connect the cable
shield to the GND terminal. If an unbalanced input is required.
connect a jumper from the GND terminal to an adjacent input
terminal.

TO HIGH

OUTPUT IMPEDANCE
TERMINAL NPUT 0F
STRIP OF POWER

DRIVER AWLIFIER
AMPLIFIER

74~0738-A
AT 70V RI I IOK, l/ZW

AT 25V HI I 3.3K,I/2Vl

Figure l - Input from another amplifier

Balanced bridging input

The inputs for two or more amplifiers may be paralleled
without loss of gain. To do this, install a Bogen Model TL-IOK
transformer in socket XI. Connect the 6009 source to the BAL
LOW Z terminal strip on the rear of the unit. Use the two
outside terminals on the strip and connect the cable shields to
the GND terminal. lfan unbalanced input is required. connect a
jumper from the GND terminal to an adjacent input terminal.

Input from another amplifier

The amplifier can be driven from a standard public address
amplifier that provides a 25~volt or 70-volt constant voltage
output. To do this. connect the output ofthe amplifierto one of
the Hi-Z lNPUTjacks via a resistor network (see figure 1). The
resistors shown in figure I are in addition to the normal
loudspeaker load on the output ofthe public address amplifier.

OUTPUT CONNECTIONS

CAUTION
Be sure to follow lam! electrical codes when
connecting amplifier oulpul.

A variety of outputs is provided from the amplifier, either

CA UTIOA" _ _ balanced or unbalanced. Refer to Table l for appropriate
RemOW 11 [WWW/0" "1" before "UM/[ms connections. Generally, the ground link does not need to be
[ram/armerr. connected unless an unbalanced output is especially desired.
TABLE 1 - Output Connections
i_.
OUTPUT IMPEDANCE (ohms) ligtfi @ @ Q @
VOLTAGE MT60A MT 12513 1 2 3 4 5 6 7
1 10V 260 125 JUMPER 1 t0 3 OUTPUT 2-7
70V 83.3 40 OUTPUT 3-7
50V 42 20 5-7
45V - I6 3-6
32.5V ~ 8 to 10 " 4-6
31V 16 - " 3-6
25V 8 to 10.5 4 to 5 3-5
* 13V 1.8 1.4 1-2
12.5V 2.5 1.25 1 3-4
'Unbalanced output only

"Disconnect link between COM and GND

Page 3

PHONC PLUfa

56 To AMP l

NWT

Figure 2 - External level control for amplifiers

70V constant-voltage output

For 70V constant voltage operation, connect the speaker
leads to the 70V and COM terminals on the rear ofthe unit. If
grounding is required. connect the link from COM to GND.

25V constant-voltage output

For 25V constant-voltage unbalanced operation, connect the
speaker leads to 25V and COM. leaving the link connected
between COM and GND. For balanced operation. open the link
between COM l and GNDI lfthe output transformer center tap
must be grounded, connect ajumper between 25VCT and GND.

CONNECTING AMPLIFIERS IN SERIES

CA U T] 0N
Connect only amplifier: of the same model in
series: do not mix different amplifier types

Bogen MTIZSB or MT60A amplifiers may be connected in
series to increase total power output where absolutely necessary

to a single speaker line. Typical output connections are shown in
Ta blc 2. Note: G ND straps on all excep/ A M P I must be opened.

Input connections

If the amplifier Hi-Z inputs are being driven directly. simply
parallel the amplifier Hi-Z inputs with a phono patch cord. and
connect the input line to one amplifier. When a balanced input
transformer is being used. parallel the inputs at the screw
terminals

Level control adjustment

It is extremely important that the amplifiers have the same
gain and produce equal power output. This adjustment is most
easily accomplished by setting both amplifier level controls to
maximum and then providing an external gain control as shown
in figure 2. Make sure speech filter switches are in the same
position. If an external control cannot be provided. amplifier
gain must be set with the use of an external tone source.
adjusting the amplifiers to produce the same output with inputs
paralleled. Always keep level controls at approximately the
same position even when setting up the amplifiers

CONNECTING AMPLIFIERS IN PARALLEL

It is not recommended that amplifiers be connected in
parallel However. this is sometimes unavoidable. If it is
necessary to connect amplifiers in this configuration, consult
our Engineering Department for instructions.

POWER CONNECTIONS

The booster amplifier may be operated from l20VAC or 48V
to 56VDC.

TABLE 2 - Amplifier Series Connection

N . l
A238. Type Total power Output Connections
AMP 1 AMP Z
O O O 0 O O 0 O O O
2 MTGOA 120M429 70v T f T f . 70v
OUT
AMP 1 AMP 2 AMP 3
3 06,0 180W289 70v oo ocfioo oogoioo oopopoo 70v
MT125B 375W.139 T3 zsv wmomes m SERIES . our
AMP 1 AMP Z
2 Mrosroit 120w, 5.252 25v 0 o o o o o 0 i 0 o 0 25V
MTlZSB 250w,2.5r2 - ' OUT
AMP 1 AMP Z
2 MTOGIOA 120w,1209 120V 0 O 0 0° 0 0° 0 o
MTlZSB 250w,53rz L-__,L_-JL tozuoy
AMP 1 AMP 2
2 O O O O O O 0 O O O
MTlZSB 250w, 20:2 70v T f 5 f I 38}!