BGW 8000 User manual

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13"1:10 SOUTM YUKON AVENue
MAWTMORNe. CAL.'''OFINIA 902~O
PMONI! (213) e73.aoeo TELEX NO. ee-44e~
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MODEL 8000 TOROID
Proline U
OWNER'S MANUAL
DESCRIPTION
Important ••
. . . . . . . . .
Description
. Product Option • . .. •
I. • • • . • •
J
Specifications • • •
I·
Unpacking &: Set-Up. • . . . . . . . . . .
Rack Mounting Hints
Input
Connections. • •
Output Connections •
Damping
Factor Nomograph
Speaker Fuse Nomograph.
Mono Operation. • • • •
Power Mains
Connection. •
Power Mains Voltage Conversion
Operation • • • • • • •
Circuit Description •
Service Instructions •
L'
.
;
I'
FORM NUMBER
00601
· . •
• 00843
00845
02303
• • • 02530
02660
• • • 02711
03431
•
•• 03.510
• • • 03530
• • • 03691
• • • 04000
04132
05202
06283
13600

00711-2
Schematic Amplifier Module.. • • · . .. . . .. . . . . . . . • •
13620
Transformer Schematics Toroids
.. .. . . 1361.5
Heatsink Assembly Component Layout. .. . ·. . . . . . . . ...
136.50
Chassis Schematic. • • • • • • • . .. . . . . . . . . .
13611
Block Diagram ••••••••
·. . ...
13630
Display Schematic
·. · . . . .. . .
13640
Parts List • • • • • • • . . . .. . ..
13690
Warranty .. . .. ..
17000
Service Authorization Form ...
17020
Warranty Registratjon Form • · .. . . .. . . ...
17030
-

50023
!-
SYSTEMS
13130 SOUTH YUKON AVe:NUE
HAWTHORNE . CALIFORNIA 90250
PHONE [phone]
TEL-EX NO . 66-4494
MODEL 8000 TEST REPORT
TECHNICIAN:-;j c1.J.J
SERIAL NO.: 0fi'IJ 13 53
LINE VOLTAGE: 12-0V
Power @ Clip (0.1% THO)
8 ohms -Volts out
Power
Power @ Clip (0.1596 THO)
4 ohms -Volts out
Power
THD 200 Watts -8 ohms
(40 Volts)
20Hz
20kHz
THD Mono - 8 ohms
650 Watts (72.2 Volts)
1kHz
Small Signal Bandwidth
-3dB Frequency
Noise Level
Output Noise Voltage
20Hz to 20kHz
Quiescent Power
Watts
CH. A
Lr7~ 3\/
Ci'1q4--
.o~ 96
%
96
.,J %
~ %
• (l J
kHz
kHz
mV. mV.
7/29/83

11 •
00601-1
-IMPORTANT -
PLEASE READ THIS PAGE BEFORE OPERATING
YOUR
BGW POWER AMPLIFIER
Your new BGW amplifier is designed to provide years of trouble free performance.
Observing
these few precautions will insure proper operation:
Read all Instructions
before connecting any AC power to your power amplifier.
Retain this Manual for future reference.
Heed all warnings on the top or rear of the power amplifier.
The amplifier should not be used near water -for example, near a bathtub,
washbowl, kitchen sink, laundry
tub, in a wet basement, or near a swimming pool,
etc.
The amplifier should be situated so that its location or position does not interfere
with its proper ventilation. For example, it should not be situated on a bed, sofa,
rug, or similar surface that may block the ventilation openings; or, placed in a
built-in
installation, such as a bookcase or cabinet that may impede the flow of air
through the ventilation openings.
The
amplifier should be situated away from heat sources such as radiators, heat
registers, stoves, or other appliances that produce heat.
The amplifier should be connected to a power supply only of the type described in
the operating instructions or as marked on the rear panel.
Precautions should be taken so that the grounding means of the amplifier is not
defeated.
The power supply cord should be routed so that it is not likely to be walked on or
pinched by
items placed upon or against it, paying particular attention to cord at
the plug, convenience receptacles, and the point where they exit from the
amplifier.
Care should be taken so that objects do not fall into, and liquids are not spilled into
the amplifier through openings.
I

00601-2
The
amplifier should be serviced by qualified service personnel when:
The power supply cord or
the plug has been damaged; or objects have
fallen into, or liquid has been spilled into the amplifier; or has been
exposed
to rain; or does not appear to operate normally or exhibits a
marked change in performance; or has been dropped, or the enclosure has
been damaged.
All connections should be made to the power amplifier with the power OFF.
Speaker fuses should be used to alford maximum speaker protection.
Never connect the output of one channel to that of another.
Connect the. power cord to the proper voltage mains as indicated on the rear of
the amplifier. Conversion to another voltage requires internal rewiring.
Do not remove the amplifier's cover. Amplifiers may not be covered under
warranty if they are tampered with. There are NO adjustments within.
Potentially lethal voltages exist within the amplifier. Refer all service work to
an authorized BGW service station.

1I~'
00843
DESCRIPTION
The
BGW Model 8000 is one of the most advanced solid state, quasi-
complementary, bridgeable, stereo power amplifiers available.
Features of the Model 8000 include Toroid Power Transformer, Forced Air Cooling,
Power Switch, CirOJit Breaker, Input Level Controls, Modular Construction,
Display
Meter Assembly, Dual Looping ~ phone jack5, and electronic DC speaker
.
protection.
The Front Panel includes two Input Level Controls, Rocker AC Power Switch and
Dual Tri Color
LED Dispaly. Green LED's indicate power ON, yellow LED's
indicate signal
presence and are labeled modulation, and red LED's serve as
overload indicators.
The
Rear Panel includes AC Input Cord, CirOJit Breaker, two sets of looping ~"
Phone Jack Input Connectors, Red and Black .5-way Binding Posts for the output of
each
amplifier, and a Mono/Stereo Switch to convert amplifier to a fully bridged
Mono amplifier.
Provisions are also available for an input accessory module. This cirOJit board
provides balanced
electronic inputs, subsonic filter and electronic crossover. The
input module can
be added at any time by a qualified electronic technician.
Both the circuit and chassis grounds are connected together internally. Refer to
MFRM 04132 for information regarding ground separation.
The Model 8000 can be used for a wide variety of applications. However, please
note the following precaution.
1) Do not use the front panel as the sole support for the amplifier. Side
rails or
rack shelves should be employed.
The
output stages of your Model 8000 use 24 Ultracase
tm
devices, the most
advanced
type of transistors available. These large geometry, 200 watt power
devices
(total 4800 watts) have large safe operating areas and extended power i
bandwidth.
Electrostatic and other highly reactive speaker systems present no I
I
difficulties for the Model 8000. I
I
I
j

0084.5
The Proline n audio power amplifier model 8000 is available from the factory with
custom options to fi t your needs.
Some of
these options may require a minimum quantity of products to be purchased
at one time. Please contact the factory with your requirements.
Some of the options for the 8000 are listed below:
8000-01
Active Electronic Balanced Li.ne Inputs
8000-02
Electronic Crossover
8000-03
Transformer Balanced tine Inputs
With Looping XLR's
8000-04 Unbalanced Line Inputs
With Looping XLR's
Rev. 7/12/84

02.303-1
THE
BGW 8000 TOROID
PROFESSIONAL POWER AMPLIFIER
Exacting design
standards and unique features establish the BG W amplifier as the
industry leader in power amplifier techn<tlRgy. Features such as all steel welded
chassis and covers, exclusive Ultracase output transistors, totally modular
construction, massive aluminum heatsinks, state of the art toroidal power
transformer and low feedback discrete circuit design have set the industry standard
in audio power amplifi ers.
Delivering a full 22.5 watts per channel into 8 ohm loads and capable of driving
loads
as low as 2 ohms. The Model 8000 offers reliability and performance
unparalleled in the industry.
SPECIFICA
nONS: BGW MODEL 8000 TOROID
OUTPUT POWER
22.5 watts minimum sine wave continuous average power output per channel with
both channels driving 8-ohm loads over a power band from 20Hz to 20kHz. The
maximum Total Harmonic Distortion
at any power level from 2.50-millwatts to 200
watts shall be no more than .0.5% from 20Hz to 10kHz and rising to no more than
.10% at 20kHz.
3.50 watts minimum sine wave continuous average power output per channel with
both channels driving 4-ohm loads over a power band from 40Hz to 20kHz. The
maximum
Total Harmonic Distortion at any power level from 2.50-milliwatts to 3.50
watts shall be no more than .1.5% from 40Hz to 20kHz.
700
wa~ minimum sine wave continuous average power output monaural driving
an 8-ohm load
over a power band from 40Hz to 20kHz. The maximum Total
Harmonic
Distortion at any power level from 2.5O-millwatts to 700 watts shall be
no
more than .1.5% from 40 to 20kHz.
*All specifications and features are subject to change without notice.

02303-2
Intermodulation Distortion:
Small Signal
Frequency Response:
Hum and Noise Level:
Input Sensitivity:
Voltage Gain:
Input Impedance:
Damping
Factor:
Output Impedance:
Power Requirement5:
Semiconductor
Complement:
Dimensions:
Weight:
SPECIFICATIONS
Less than 0.05% from 250 milliwatts
to rated output power.
+0, -3dB, 1Hz to 100kHz,
+0, -0.25dB, 20Hz, to 20kHz.
Better than 1l0dB below 225 watts
into 8 ohms. (A weighted).
1.23 volts for
rated power output.
34.5 times.
15k ohms.
Greater than 200 to 1 at 8 ohms.
Designed for any load impedance
equal to or
greater than 2 ohms.
120 volts A.C., 60Hz at 14 amps Also
availab
le for 100, 220 or 240 volts
A.C.,50Hz.
2 Ultra-low noise matched differential
pairs, 64 transistors, 32 diodes, 6 LED's,
2 Triacs, and 5 Zener diodes.
5 1/4" by 19"
standard rack front panel.
Depth behind
front panel: 5" x 17 x 13.
(13.35 cm x 48.26 cm x 33.02 cm)
49~ Lbs., 22.50 kg shipping
43~ Lbs., 19.77 kg net

02530
I'
I UNPACKING
AND SET-UP
I Your
BGW Power Amplifier is shipped in an advanced packing container.
SA VE THE CONTAINER
AND ALL PACKING MATERIAL!
The
container should be saved in the event the unit is moved or shipped at some
future date. Replacement containers are available from BGW Systems•
.Inspect the unit for damage in transit immediately upon receipt. If damage is
found, notify
the transportation company immediately. Only the consignee may
institute a claim with the carrier for shipping damage. BGW will cooperate fully in
such an
event. Be sure to save the container as evidence of damage for the shipper
to inspect.
The amplifier's mounting position must
be chosen carefully, so that the air flow to
the front and rear of the unit is not restricted. Inadequate ventilation may cause
failure of the amplifier. For rack mounting, the four rubber feet on the bottom of
the unit may be removed and no hardware will be loosened inside
the unit.
Do not, however, use the front panel as the sole support for the amplifier. Side
rails or rack shelves should be employed.
DO NOT PLUG THE AMPLIFIER IN YET!
All connections should be made before power is applied.

02660
RACK MOUNTING HINTS
KEEPING
IT COOL
A power
amplifier draws energy from a primary electrical service, usually a
120volts AC
outlet, to drive loudspeaker systems with an audio signal. Typically,
only
half of the energy can be delivered to the loudspeakers; remaining energy is
converted into heat, and must be dissipated (ventilated) into the air.
Air circulating past heat-producing components absorbs the heat and carries it
away. To accomplish this, low and medium power amplifiers rely on natural
convection
currents, while most high power amplifiers use fans. If the air flow is
impeded, the resulting rise in heat may cause an amplifier to stop working or fail.
Circulating air currents must not be cut off when installing power amplifiers in
racks. Power amplifiers using convection cooling require spacing between
amplifiers to permit air flow between them. Power amplifiers using forced-air
cooling, on the other hand, can usually be stacked closer to each other and may not
need.any blank panel spacing between amplifiers.
To improve natural convection currents within a rack, a chimney can be created by
closing
the back of the rack and venting the rack at the bottom to let in fresh air,
and at the top to exhaust hot air. Vents should be large rectangular slots
approximately 19" wide by 411 high.
The
rack cabinet will require some type of blower if a large air-flow is required. It
is best to exhaust air from the top of the rack rather than to blow it in from the
bottom. There will t>e less dust and dirt in the rack this way, if the bottom vent is
sufficiently large.
INSTALLING THE UNITS
When racks are to be transported or used in mobile installations, some means of
securing
the rear of the equipment is required. Angle brackets attached either to
the bottom, sides or rear panel are practical approaches.

1 , \J.JI.I'8 a.
02711
STEREO INPUT CONNECTIONS
Dual looping
~" in. phone jacks are provided on the rear of the amplifier for input
connections.
1/4 INCH PHONE JACKS
The 1/4" phone jacks
are for unbalanced lines only (single conductor, shielded).
Simply
connect the shield to the outer sleeve of the plug and the inner conductor to
the tip, or buy ready-made cables. See diagram below.
Connect shield here ~
~~f ...,.,r~~=====C:::=~::::~~/""'--~
Connect inner conductor here sleeve tip
FOR MONO (BRIDGED) OPERA nON
To operate the unit as a Mono amplifier, use the Channel "A" input only. DO NOT
use
the Channel "B" input. Remember to place the Stereo/Mono switch in the
'I
Mono position. Refer to Page 03691 for Mono Operation.
!

03431
STEREO OUTPUT CONNECTIONS
MOdel 8000
Two
sets of five-way binding posts, on the rear panel, serve as output connectors,
with one black and one red binding post for each channel. Channel IIA" leads go to
the binding posts marked Channel "A"; Channel "B", to those marked Channel "B".
Output leads are best connected, to the amplifier, with standard banana plugs;
however,
the five-way action of the binding posts permits the use of tinned wires
or spade lugs.
Make
certain that the speakers are properly phased. Connect the black or minus (-)
terminal on the speaker cabinet to the appropriate black binding post on the
amplifier. Connect the red or plus (+) terminal to the red binding post. Check to
see that the Stereo-Mono switch on the rear of the amplifier is in the Stereo
position.
SPEAKER PROTECTION
The Model 8000 has DC load (speaker)
protection built into the heat sink module,
however,
all speakers can be damaged by having too much power appJied to them.
Fuse protection is an effective and inexpensive way of preventing this from
occurring. If your speaker system does not contain a fuse or a circuit breaker, a
fuse should be placed in series with
each speaker and the wire going to the red
terminal on the rear of the amplifier.
Maximum protecti~ can be obtained with fast-acting fuses. Use the value
recommended by the manufacturer. If no value is specified, use the chart provided
to select the correct value. See page 03530.
To use
the chart, take a straightedge, such as a ruler, and line up the speaker's
impedance with its peak music power rating. The proper fuse value can then be
read from the center column. Choose a fuse that is closest to, and below, the
value indicated.
WIRE SIZE AND DAMPING FACTOR
The high damping
factor of BGW amplifiers results in very clean bass response.
Excessively long, or small
diameter speaker wires can lower the damping factor
and distort low frequencies. A damping factor of at least 50 should be maintained
to insure good audio quali ty.
The relationship between wire Jength and diameter, and damping factor can be
calculated using the chart (MFRM-03510) on the foHowing page. Proceed as
follows:
1. USing a straight-edge, line up the gauge of the speaker wire with its length.
Mark off the resulting source resistance where this line crosses the center
column.
2. Line up the source resistance, determined in step 1/ l, with the
manufacturer's impedance of the speaker system. The damping factor can now
be
read.

-- ~--
. _. ..- ,, _ . - _. _._ .-
-- - .. - - -._- - -- - --
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AHNIALID
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RlSfSTAHCI . IISISTAHCI
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ret-e,
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EXMfPLE: RL • SO. RS ... 0412 OR D.F ... 200
CABLE LENGTH OF 20 FT. ANSWER: #10 WIRE
SOURCE RESISTANCE AIID DAMPING FACTOR VS. LENGTH AND SIZE OF OUTPUT LEADS
MFRM -03510

."--.--0....- _ _ __ _ _
4
5
•
7
1 •
10
12
14
16
20
2S
SPEAKER 1
, ....... )
EXAMPLE:
~ -
8n,
PEAK
POWER
FUSE
SELECTOR NOMOGRAPH
5
4
.2
J5
.1
.oa
FUSE
( ..... ,
400
300
200
150
100
10
60
40
30
20
PEAK
15
MUSIC
10 POWER
1
(watta)
•
4
3
2
1
SPEAKER
= 150W.
ANSWER:
FUSE ,. 2 AHPS
FOR LOUDSPEAKER PROTECTION
MFRM -03530

· ~ ...
03691
MONO OPERA nON
The output power of the amplifier can be increased by operating it in the Mono
(bridged) mode. The
correct procedure for Mono operation is as follows:
1. Set Stereo/Mono switch to Mono position.
2. Use channel "A"
input only. DO NOT use the channel "B" input.
3.
Connect the output across the two Plus (+) Terminals. DO NOT use the Minus
(-) Terminals. DO NOT reference the load (speaker) to ground. Designate channel
"Art as Plus (+) and channel "B" as minus (-). Fuses, when necessary, should be
placed in
series with one of the Plus .(+) Terminals.
"B" Channel "A" Channel
Input
.
Output
O©8
OCOCV
©@J
©~
mJ~
Output
Input
MONO STEREO
NOTE: Minimum load
impedance for Mono operation should be 8 ohms;
CIRCUIT DESCRIPTION
In
the Mono mode, the output of channel "Art is fed into the inverting input of
channel"B". The two channels work opposite each other; when one goes positive,
the other goes negative, thus doubling the output voltage swing. The single output
is referenced between the two red binding posts.

04000
POWER MAINS CONNECTIONS
The
unit should be plugged in only when it has been established that it is wired for
the correct power mains voltage and after all other connections have been made.
The mains (AC line) voltage is indicated on the serial number label on the rear of
the unit. Products supplied for use in the United States and Canada are factory
wired for 120 volts. Only the indicated mains voltage should be used. If the mains
voltage must be changed, see POWER MAINS VOLTAGE CONVERSION.
A molded,
parallel blade, U-ground plug is supplied. This connector is standard in
the United States and Canada. For use elsewhere, the plug must be replaced with
the correct connector. The color-code of the cord is as follows:
HI (switched Le$) -Brown (or Black)
LO
(neutral Leg) -Blue (or White)
EARTH (Chassis ground) -
Green with Yellow tracer (or Green)

04132
POWER
MAINS VOLTAGE CONVERSION
CAUTION: These servicing instructions
are for use by qualtiied personnel only.
To avoid electric shock, do not perform any servicing other than
that contained in the Operating Instructions, unless you are qualtiied
to do so. Refer all servicing to qualified service personnel•
. NOTICE: .Voltage con-.:ersion should be done
by a BGW Authorized service
station only.
The Model 8000 is shipped from
the factory wired for correct operation in the
country in which it is to be sold. The schematic diagram, MFRM 13610 and 13611
indicates the connections for other voltages.
CHASSIS
AND CIRCUIT GROUNDS
Both chassis and
circuit grounds are connected together internally. They can be
separated by removing the Black wire connected to grounding lug under the "B"
module near
the AC power cord. The circuit grounds of all active units (amplifiers,
preamplifiers, mixers,
etc.) can be tied to earth ground at a common point. This
aids
in eliminating ground loops.

0.5202-1
OPERATION
PRECAUTIONS
1. Speaker destruction is often due to improper equipment operation. This often
occurs when someone without the proper appreciation for the components of
a high power, high quality music system, has the opportunity to change
records or adjust levels. The best protection here is caution. Keep the
equipment out of reach of untrained adults and children. Make sure the
speaker is properly protected with fuses (Output Connections Section).
2. Never parallel the two amplifier outputs together.
3. If the amplifier continuously trips its circuit breaker, something is wrong -do
not continue operation.
4. Do not connect an input ground lead to an output ground lead; to do so may
cause a ground loop and oscillations.
.5.
Do not operate the amplifier from power mains ·which exceed the indicated
mains voltage by more than 1096.
6. Never connect the output of the amplifier to another power source such as a
battery or power main.
7. Do not expose the amplilier to corrosive chemicals such as lye, soft drinks,
salt water, etc. Also, never immerse the amplifier in any liquid.
8. Do
not remove the amplifier's cover during operations.
9. The amplifier is not intended for high frequency-high power use and should
not be used for high power ultrasonic applications.
10. Neither the amplifier nor any of its leads should be exposed to areas likely to
be struck by lightning.
PROCEDURES
After all connections have been made to the power amplifier, tum the gain
controls fully counter-clockwise. Tum on the preamplifier or mixer, then tum on
the power amplifier. The two green LED's on the front panel should light. If they
do not, check to see that the amplifier is plugged in to a live power outlet.
,/ -.

0.5202-2
With the preamplifer or mixer gain controls fully off, advance the power amplifier
gain controls about half way dock-wise (slit in knob facing upwards). There ahould
be no
audible hum; if a hum is heard, check the connections between the power
amplifier and preamplifier. Now advance the preamplifier gain controls until the
desired maximum volume is achieved. Should the preamplifier gain control be in
excess of the 3/4 setting, decrease it to ha1:f volume and increase the gain controls
of the power amplifier to the desired level.
Often, tum-on transients originate in the pre-amp or mixer. This is especially true
of tube-type units. If this situation arises, tum the amplifier on after the other
units have had adequate time to stabilize.