Equipment information

JBL 6290 Amplifier
Manufacturer
JBL
Model 6290
Date 1988
Category Audio, Video, TV, Multimedia
Group Amplifier
Description Power Amplifier
Information
                                    The JBL Model 6290 power amplifier has been designed to meet
the most critical professional sound requirements. It Is
rugged and road-worthy, conservatively rated, and can handle
reactive loads with ease.

The engineering design approach stresses the optimization of
each stage, allowing high slew rate and relatively low loop
gain. Overall feedback has been held to a minimum and is
employed only to stabilize the gain and the operating point.
This design approach results In an amplifier with excellent
performance under the most demanding dynamic input and load
conditions. As evidence of the stress on dynamic rather than
static or steady-state distortion mechanisms, transient
Intermodulation distortion measures less than 0.03$ by the
DIM 100 test. (Leinonen, Otala, and Curl, "A Method for
Measuring Transient Intermodulation Distortion (TIM)”,
JournaI of the Audio Engineering Society, Vol. 25, No. 4,
April, 1977, pp. 170-177.)

This JBL amplifier uses multiple 200-watt output devices in
complementary configuration for high reliability and low
distortion. At rated power Into 8 ohms, these output devices
are operated at less than 25% of their rated power
dissipation. The benefit Is high reliability and long
component life.

Reliable operation Is ensured through the following
protection modes: current Is limited under Improper load or
drive conditions; output relays with front panel Indicators
protect the loudspeaker under conditions of DC offset or
excessive low-frequency transients. The relays also provide
power-up, power—down, and "brown out’1 muting to protect
loudspeakers from AC power transients. Clip Indicators allow
for system optimization.

The JBL amplifier may be operated In the normal stereo mode,
dual mono mode, or bridged mono mode. These modes are switch
selectable on the rear panel.

Active differential Input circuitry offers the benefits of
balanced operation without the use of Input transformers.
Input connections may be made via 3-pln XL-type connector,
three-conductor (TRS) 6.3 mm (1/4 In.) phone jack, or
barrier strip. The barrier strip has separate terminals for
audio ground and chassis ground.

The rack ears and heatsink of the amplifier are made of high
grade aluminum extrusions; the chassis Is fabricated of
heavy gauge steel. All Internal components are easily
accessible through removal of top and bottom panels. Front
panel graphic details are Incorporated on the rear-side of a
polycarbonate laminate which is virtually Indestructible.

These manuals are available for the above equipment:

Manual Type Service and User Manual JBL-9808-Manual-Page-1-Picture
Pages 30
Size 3.07 Mbytes (3220037 Bytes)
Language english
Revision
Manual-ID/Number
Date 01 January 1988
Quality Scanned document, all readable.
Upload date
MD5 edf2136941c801cfc6108848e3b215fb
Downloads 78 since 29 October 2017
Information
SECTION I. INTRODUCTION	1-1
1.1	SPECIFICATIONS	1-2

SECTION II. INSPECTION AND INSTALLATION	I 1-1
2.1	UNPACKING AND INSPECTION	11-1

2.2	ENVIRONMENTAL CONSIDERATIONS	11-1

2.3	AC POWER	11-1

2.4	AMPLIFIER MODE SWITCH	11-2

2.5	EXTERNAL CONNECTIONS	11-3

2.5.1	INPUT CONNECTIONS, GENERAL	11-3

2.5.2	INPUT CONNECTION, DUAL MONO MODE	11-3

2.5.3	INPUT CONNECTION, BRIDGED MONO MODE	11-3

2.5.4	FIVE-WAY BINDING POST OUTPUT CONNECTORS	11-4

2.5.5	ABOUT OUTPUT POLARITY AND BRIDGED MONO	11-4 CONNECTION

2.6	INPUT IMPEDANCE AND TERMINATION	11-4

2.7	APPROPRIATELY RATED LOADS	11-6

2.7.1	IT IS THE USER’S RESPONSIBILITY TO AVOID	11-6
OVERPOWER ING

2.7.2	MORE ABOUT LOUDSPEAKER POWER RATINGS	11-6

2.7.3	SOMETIMES A LARGER AMPLIFIER CAN BE SAFER	11-7

2.7.4	REMEMBER THE DIVIDING NETWORK (CROSSOVER)	11-8

2.8	SPEAKER CABLES	I 1-8

2.8.1	TYPE OF WlRE	I I-8

2.8.2	DAMP ING FACTOR	I I-8

2.8.3	CALCULATING LOSSES IN SPEAKER CABLE	I I-9

2.9	GROUNDING	11-10

2.10	SECURITY COVERS	11-10 FIGURE 2-1 BALANCED INPUT
CONNECTIONS	11-11 FIGURE 2-2 UNBALANCED INPUT CONNECTIONS
11-11 FIGURE 2-3 BARRIER STRIP CONNECTIONS	11-12 FIGURE 2-4
USE OF FIVE-WAY BINDING POSTS	11-13 FIGURE 2-5 OUTPUT
CONNECTIONS TO TWO CHANNEL	11-13

SPEAKER SYSTEM

FIGURE 2-6 BRIDGED OUTPUT CONNECTION TO MONAURAL	11-13
SPEAKER SYSTEM

SECTION III. OPERATING INSTRUCTIONS	I I 1-1
3.1	GENERAL	I I 1-1

3.2	TURN ON AND SYSTEM CHECK	MI-1

3.2.1	A NOTE ON AMPLIFIER COOLING	111-1

3.3	CLIP INDICATORS	II 1-1

3.3.1	ABOUT SENSITIVITY RATINGS	111-2
SECTION IV. THEORY OF OPERATION	IV-1

4.1	INPUT DIFFERENTIAL AMPLIFIER	IV-1

4.2	MODE SWITCH	IV-1

4.3	POWER AMPLIFIER	IV-1

4.4	RELAY DRIVER/OUTPUT DC DETECTOR	IV-2

4.5	CLIP CIRCUIT	IV-3

4.6	POWER SUPPLY	IV-3

SECTION V. MAINTENANCE	V-1

5.1	GENERAL	V-1

5.2	REPAIRS AND WARRANTY	V-1

SECTION V I. SCHEMATIC DIAGRAM
JBL-9808-Manual-Page-1-Picture


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