TECHNICAL SPECIFICATIONS
Rated Output Power:
Model BPA-60
Model BPA- 125
60 watts (rms) from 50Hz to
125 watts (rms) from 5OHz to
15kHz at less than 2% THD
into rated load impedances
I5kHz at less than 2%THD
into rated load impedances
-2dB from 20Hz to 2OkHz
Frequency Response:
High-impedance: 300mV;
Low-impedance, balanced: 75mV with accessory transformer Model TL600
Input Sensitivity:
Better than 2dB from no load to full load
Output Regulation:
85dB below rated output
Hum and Noise:
High-impedance: 50k-ohms unbalanced;
Low-impedance: 600-ohms balanced, with accessory transformer TL600;
Line-bridging with accessory transformers TLl00 or TLlOK
Inputs (Impedance):
4-ohm/25V, 16-ohms,
25VCT and 70V
8-ohm/25V, 16-ohms,
25VCT and 70V
Output Loads:
-1OdB @ 1OOHz (Switch-Selectable)
Lo-Cut Filter:
Controls, Indicators;
Front Panel:
Rear Panel:
Illuminated Power Switch
Input Level Control; Circuit Breaker Reset Switch; Lo-Cut Filter Switch
Power Consumption;
I20VAC, 60Hz
@ Full Rated Output:
18OW
360w
I
1
Overload Protection:
AC Circuit Breaker. Thermal Circuit Breaker, Transient Protection Diodes
Auxiliary Receptacle:
(not switched)
Three-wire grounded* 300 watts maximum
15.25”Wx8”Dx5.25”H
(38.7 x 20.3 x 13.3 cm)
15.25”Wx8”Dx3.5”H
(38.7 x 20.3 x 8.9 cm)
Dimensions:
I
Finish:
Black
19 lbs. (8.6 kg)
27 Ibs. (12.3 kg)
Rack Panel Brackets:
RPK-53
RPK-54
Accessories:
Model TL600, 600-ohm line-matching transformer
Model TLIOO, 1:1 ratio transformer
Model TLlOK, 10,000-ohm line-matching transformer
Weight:
1
*This receptacle will be grounded only if the power amplifier has been grounded properly
All specifications subject to change without notice
AMPLIFIER
1
G N D COM 25VCT
AMPLIFIER 2
GND COM 25VCT
IMPEDANCE
INPUT O F
POWER
AMPLIFIER
OUTPUT
TERMINAL
AMPLIFIER I
G N D C O M l6fi
sz&RoF
AMPLIFIER
AMPLIFIER 2
G N D C O M lGfI
-0730-A
A T
I
AT
A74-2021-01
7OV R I = 10K, 1/2W
25V
R I = 3.3K, 1/2W
Figure 2 - Input From Another Amplifier
Figure 1 - Connecting Amplifiers in Series
2
Figure 3 - BPA-60 Rear Panel Connection Diagram
CONNECTING AMPLIFIERS IN SERIES. Pairs of the same
amplifier model may be connected in series to effectively double the power output into the same load line (see Figure 1). Be
certain to remove the link between COM and GND terminals
on amplifier No. 2.
Connect speaker systems directly to the output terminal strip on
the rear panel. Connect one speaker lead to the COM terminal and
the other to the terminal corresponding to the impedance of the
speaker system. If the load impedance falls between two output terminal values, use the terminal of lower impedance. Total power
distribution to the speakers should not be greater than the power
rating of the amplifier. For balanced output lines, remove the link
between the COM and GND terminals. If the line is shielded, connect the shield to the GND terminal. For unbalanced speaker lines,
close the link between the COM and GND terminals.
BRIDGING INPUT. The inputs of two or more amplifiers may
be paralleled by installing accessory transformer TLlOO (for up
to 6 amplifiers) or TLlOK (for more than 6 amplifiers) in the
transformer socket designated XT-l (see Figure 5) on the
printed circuit board. Connect the signal source to the BAL
LO-Z terminal strip and connect the cable shield to the GND
terminal. For an unbalanced input, connect a jumper wire from
the GND terminal to an adjacent input terminal.
HUM. If the connections between the signal sources and amplifier
are incorrect or defective, hum-type interference may occur. Check
for proper grounding, broken wires, shields, poor connector contacts, etc. Keep input cables away from speaker cables and speaker
cables away from AC power lines. Where a turntable or other auxiliary equipment is used, it may be necessary to connect a separate
ground wire from the chassis of such equipment to a suitable earth
ground.
INPUT FROM ANOTHER AMPLIFIER. The BPA-60 and
BPA-125 amplifiers may be driven from an amplifier that provides a 25-volt or 70-volt constant voltage output. Connect the
output of the driver amplifier to one of the HI-Z input jacks via
a resistor network (see Figure 2). These resistors are in addition
to the normal loudspeaker load impedance on the output of the
driver amplifier.
POWER. The POWER switch applies power to the amplifier; it
does not control any associated equipment which may be connected
to the auxiliary power receptacle on the rear panel. The switch lamp
will illuminate when power has been applied to the unit.
OUTPUT CONNECTIONS
LO-CUT FILTER SWITCH. The LO-CUT filter switch, located on
the rear panel, provides -1OdB attenuation at 100Hz.
CAUTION
Follow local electrical codes when connecting ampljier
output.
INPUT LEVEL CONTROL. The INPUT LEVEL control, located
on the rear panel, adjusts the input signal applied to the amplifier.
Turn the adjustable screw clockwise to increase the level.
Fires 3 and 4 show the location and impedance values for the
output terminal strip. Class 2 wiring is acceptable for output loads.
CAUTION
Many loudspeakers may be damaged if overdriven.
Therefore, always begin system setup with the input
level control fully counterclockwise and gradually increase the setting to obtain the desired output level.
SPEAKERS. The amplifier may be used with most conventional
speaker systems. For detailed information on the installation of
multiple speaker systems, refer to the Speaker Installation Bulletin
(No. 54-5001) included with this unit.
4
Figure 4 - BPA-125 Rear Panel Connection Diagram
THERMAL BREAKER. If the thermal breaker opens, there will be
no audio output; however, the power switch lamp will remain illuminated. Wait approximately two minutes for the breaker to reset. If
it resets and then opens again, investigate the cause of the
temperature overload. This may be due to improper connections at
the output terminals or to excessive environmental heat with inadequate ventilation. The thermal breaker will open when the
temperature at the output transistor heat sink reaches 105 °C.
CIRCUlT BREAKER.
. If the AC circuit breaker opens, the power
switch lamp wiIl go out and the amplifier will have no output;
however, there will be power at the AUX POWER receptacle on the
rear panel. Set the POWER switch to OFF and momentarily depress
the red button on the circuit breaker to reset it. Return the POWER
switch to ON. If the circuit breaker trips again, do not attempt to
reset it; have the trouble investigated by a qualified technician.
MAINTENANCE
CAUTION
There are no user-serviceable parts within the
amplifier. Have all internal servicing performed by a
qualifed technician. The warranty will become void if
repairs are made by other than the Bogen Service
Department or authorized service agency.
BOGEN SERVICE
Our Service Department is interested in the maintenance of
your Bogen equipment. If trouble ever develops, do not hesitate
to ask our advice or assistance. Information may be obtained by
writing to: Service Department, Bogen Division, P.O. Box 500,
Paramus, N.J. 07653.
When communicating with us, give the model and series
designation of your unit. Describe the difficulty and include
details on the electrical connections to associated equipment,
such as preamplifiers, speakers, etc. We will send you service information if the trouble appears simple. If the amplifier requires
servicing, we will send you the name and address of the nearest
authorized Bogen service agency.
When shipping the amplifier, pack it well, using the original
shipping carton or similar container and filler material to prevent
damage in transit. Remove any plug-in transformer from the
printed circuit board beforeshipping. Send the unit, fully insured
and freight prepaid via UPS or other responsible carrier. The
repaired unit may be picked up by you personally or will be
returned to you freight prepaid while in warranty.
REPLACING COMPONENTS
All semiconductor components on the printed circuit board
are soldered in place to ensure maximum reliability. When
soldering or unsoldering transistors and diodes, use a heat sink
(such as a small alligator clip) between the source of heat and the
component. When replacing driver and output transistors, be
certain to install the case/heat sink insulator, after lightly coating
both sides with a thermal conducting compound (such as Dow
Corning No. 340, or equivalent).
REPLACEMENT PARTS
Most components used in the amplifier are standard parts
available through reputable parts suppliers. The parts listed here
may be obtained through Bogen distributors, service agencies or
directly from the factory. When ordering a part, specify the part
number and the description, as listed. Specify the model of the
unit and give the series designation, which is a letter followed by
numbers, located on the rear panel. For parts on the circuit
board, also give the component board assembly number, which
begins with “45”.
TRANS. SKT. XT1
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0
Figure 5 - BPA-60/BPA-125 Printed Circuit Board
PARTS LIST
Designation
Part
Number
Description
Schematic
Designation
Part
Number
CBlOl
94-0023-10
CB102
CB201
CR101
CR201 -204
QlOl
4102,103
Q104-107
94-0014-07
94-0023-05
96-5373-01
96-5241-01
96-5213-01
96-5385-01
96-5385-01
R101,102
76-114-107
R103-106
76-l 14-102
R107
75-154-182
R109
R201,203
75-742-101
76-l 14-102
R202
75-154-132
SW101
TlOl
T102
T201
T202
-
81-009-036
83-831-000
83-492-000
83-814-000
83-491-000
14-9088-01
Description
PC Board
c2
C3,4
C6
CR1-4
:;
;:
Rl
R3
R4
R5
Rl8,19
Sl
-
45-7241-05
79-l 19-001
79-008-065
79-008-062
96-5333-01
96-5643-01
96-5365-01
96-5459-01
96-5458-01
77-001-818
75-154-124
75-154-154
75-154-334
76- 107-096
81-003-067
70-9302-01
Ptd. Cir. Bd. Assy.
Cap., Elect., 470 µF, 63V
Cap., Elect., 10 µ F , 63V
Cap., Elect., 100 µF, 50V
Diode, 4OOprv @ 1A
Transistor, KTC2240
Transistor, MPSA56
Transistor, 2N6292
Transistor, 2N6107
Control, Scr. Adj., 100 kilohm
Resistor, 120 kilohm, ¼ W , 1%
Resistor, 150 kilohm, 1/4W, 1%
Resistor, 330 kilohm, 1/4W, 1%
Resistor, .82 ohm, 2W
Switch, Slide, Miniature
Clip, Heat Sink (2)
Chassis
Cl01
Cl03
78-200-l 16
79- 118-002
Cl04
79-118-004
C201
79-118-006
C202
79-509-056
Cap., Cer. Disc, 0.01 µF, 1400V
Cap., Elect., 13,000 µF, 40V
(BPA-125)
Cap., Elect., 8800 µF, 75V
(BPA-125)
Cap., Elect., 5000 µ F , 50V
(BPA-60)
Cap., Elect., 6000 µ F , 75V
(BPA-60)
6
Breaker, Circuit, 4.OA
(BPA-125)
Thermostat
Breaker, Circuit, 1.6A (BPA-60)
Rectifier, Bridge (BPA-125)
Diode, 300prv @ 3A (BPA-60)
Transistor, 2N5089
Transistor, 2N3055H, RCA
Transistor, 2N3055H, RCA
(BPA-125)
Resistor, 3.3 ohm, 5W
(BPA-125)
Resistor, 0.27 ohm, 5W
(BPA-125)
Resistor, 1800 ohm, 1/4W, 1%
(BPA-125)
Resistor, 100 ohm, 7W
Resistor, 0.27 ohm, 5W
(BPA-60)
Resistor, 1300 ohm, 1/4W, 1%
(BPA-60)
Switch, Power
Transformer, Power (BPA-125)
Transformer, Output (BPA-125)
Transformer, Power (BPA-60)
Transformer, Output (BPA-60)
Foot, Rubber