DOWNLOAD JBL GTQ 190 (serv.man2) Service Manual ↓ Size: 188.31 KB | Pages: 15 in PDF or view online for FREE

01

Owner’

s Manual

Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2

Features  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2

About Installation  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2

Quick Start  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3

System Design Using the GTQ190 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3

Speaker Requirements  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3

Signal Sources  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4

Other Components  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4

Typical Applications  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4

Warnings and Tips  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5

Installation Precautions  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5

Mounting Locations  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6

Installation and Use  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6

Controls and Connectors  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6

Mounting Positions  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7

Wiring  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7

Power Supply Connections  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7

+12V Battery Wire  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7

Ground Wire  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

8

Remote Connection  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

8

Speaker Connections  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

8

Audio Input Connections  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

9

Line-Level Input Connections  . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

9

Speaker-Level Input Connections  . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Simultaneous Speaker-Level 

+

Line-Level  . . . . . . . . . . . . . . . . . . . . 10

Mode Switches  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Adjusting the Gain  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Other Important Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Add-On and Upgrade Steps  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

In Case of Difficulty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Solving Noise Problems  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

System Noise  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Vehicle Noise  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Specifications  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Maintenance  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Model Number

Serial Number

Dealer Name

City, State, Zip

Sales Receipt Number

Date of Purchase

GTQ 190 - English  06/03/98 11:49  Side 1

02

for purchasing your new GT

series automotive multi-channel ampli-
fier. Your GT series amplifier will easily
connect to virtually any car audio
system, whether it is factory installed or
purchased separately. The GTQ190
includes an abundance of unique
features which are described in this
manual. The flexible design of its built-in
crossover circuitry allows elaborate
systems to be built more simply than
with conventional components. For
optimum performance, the power
amplifier circuitry is a fully-discrete
design notable for its low distortion and
unusually clean and clear sound quality.
In addition to conventional preamp-level
inputs, the GTQ190 features JBL’s
Universal Interface, which facilitates
simple connection to factory radios with
the low distortion that is usually only
associated with preamp-level
connection. With the Universal Interface,

a factory radio can either be used as the
main music source or simultaneously
combined with a CD player or changer
that has volume-control capability. By
providing this two-unit direct connection,
Universal Interface circuitry eliminates
the need for an FM modulator to
interface a CD player to factory radios,
improving the fidelity of digital playback.
In addition, when using a high-powered
(BTL) radio through the speaker-level
inputs, Common Sense turn-on circuitry
senses the common-mode voltage pres-
ent on the radio’s speaker wires, turning
the amplifier on without an additional
remote wire.
Also, the built-in active crossover
provides either full-range, high-pass or
low-pass operation. This lets your GT
series amplifier power either subwoofer
or component speakers in a bi-amplified
system, or conventional full-range
speakers in simpler systems.
The GTQ190 also includes preamp-level
outputs which provide a full-range signal
to drive additional amplifiers. This lets
you build systems of virtually any design
without requiring a separate electronic
crossover.

• 4-, 3-, or 2-Channel Operation
• Simultaneous Stereo + Mono
Operation
• 2 Built-In Independent 18dB/Octave
Frequency Selectable High-Pass and
Low-Pass Crossovers
• 2 Pairs of Preamp Outputs
• No Current Limiting
• Oversized Floating Rail MOSFET
Switch-Mode Power Supply
• “Common Sense” 2-Way Turn-On with
Remote-Out Capability to Turn On Other
Amplifiers or Signal Processors
• Switchable Bass Boost
• “Stealth Remote” Silent Turn-On
Circuitry with Power-On Indicator
• Balanced Speaker-Level Inputs
• Mute Input – Accepts Standard Noise
Gate Input to Silence the Amp During No
Music Conditions
• 2 Continuously Adjustable Gain
Controls
• Capable of Single-Ended Operation into
2-Ohm Loads
• Fully Complementary, Direct-Coupled,
Discrete Power Amplifier Circuitry
• Gold-Plated RCA Input Connectors
• Gold-Plated Power and Speaker
Connectors
• Third Order (18dB per Octave)
Capacitive/Inductive Power-Supply
Filtering
• Independent Input Mode Switching for
Each Group of Channels
• Made in USA

Although the GTQ190 is designed to
make installation as easy as possible, this
is an extremely sophisticated product
that requires proper installation and
setup to realize its full performance
potential. Skill with tools, an
understanding of basic electronics, and
experience with car stereo installation are
needed to properly install this amplifier. If
you feel you do not have the necessary
knowledge and skills, we strongly
recommend that the installation be done
by your authorized JBL dealer. If the GTQ
amplifier is installed by an authorized JBL
dealer in the USA, we will double the
length of your warranty to two years
from date of purchase. Please retain a
copy of your bill of sale to ensure this
additional coverage.
If you choose to install the GTQ amplifier
yourself, read all of the information in
this manual before you start the
installation. Pay particular attention to the
safety precautions and notes.
It will save potential problems later if you
take a few minutes to plan the complete
installation before you start. The routing
of wires, the power supply connection
points, and the mechanical installation of
the unit should be completely thought
out before you begin. Work carefully and
check each step as it is performed. Before
operating the amplifier, recheck the entire
installation to be sure that each
connection is correct, properly insulated
and secure.

GTQ 190 - English  06/03/98 11:49  Side 2

03

Owner’

s Manual

Recommended for Experienced
Professional Installers Only!
1. Disconnect the negative cable from the
battery. Note: If the vehicle’s radio
features a code-type security system,
make certain you know the code before
disconnecting the battery!
2. Run a power cable complete with a
fuse (not included) directly from the
positive +12V battery terminal to the
desired amplifier location. Keep the fuse
within 6" of the battery terminal, and
position it before the wire runs through
any metal partition. A minimum of
#10AWG is required for the GTQ190, as
is a 30A fuse.
Note: All wiring connections should be
made either by soldering with heatshrink
tubing insulation, by using commercially
available high-quality distribution blocks,
or with high-quality crimp-type insulated
connectors installed with a professional-
type, articulated crimping tool. Soldering
crimp-type terminals is recommended
for additional security. Never use wire
nuts, insulation-displacement connectors
(i.e., ScotchLok type), or twist and tape
connections. Do not use electrical tape; it
will loosen with age and extreme
temperatures.
3. Mount amplifier in the desired location
using the included screws.
4. Connect power wiring as shown in the
Wiring Diagram on page 7.

5. Connect the outputs from the head unit
to the appropriate inputs of the amplifier
according to the Wiring Diagram (page 7)
with either (or both) high-quality low-
level signal cables with RCA plugs, or the
supplied speaker-level input connector.
6. Connect the speakers to the amplifier
according to the Wiring Diagram on 
page 7.
7. Turn the gain controls to the 1/4-
position for all groups.
8. Set the bass boost of each group to the
desired position.
9. Set the crossover switches for each
group as desired.
10. Set the Group 2 Input as desired.
11. Set the mode switches to Stereo, 
Left + Right, or Left Input Only operation
for each group.
12. Double-check your switch settings.
Reconnect the negative battery cable.
Note: Incorrect switch settings can
damage your speakers!
13. Turn on the signal source at a low
volume level, and check for the correct
output from each speaker.
14. Adjust the amplifier gain controls
using the procedure described in the
“Adjusting the Gain” section (page 11).
15. Read the rest of the manual to get
maximum use and enjoyment from your
amplifier.

When used in the non-bridged mode, a
group-channel of the GTQ190 can easily
drive two 2-ohm speaker loads. When
only one speaker is connected to the left
and right outputs of a group, virtually any
conventional speaker may be used. When
two speakers are connected in parallel to
a single output (left or right) of a given
group, each speaker must have a
minimum impedance of 4 ohms. This
ensures that the combined load will not
drop below 2 ohms. Although the
amplifier will not be damaged, load
impedances lower than 2 ohms will
eventually cause the amplifier to
overheat, activating the protection
circuits and causing the unit to shut off
until it cools down sufficiently.
When a group is in bridged mode, the
combined impedance of the speaker (or
speakers) connected to the bridged
channels should be at least 4 ohms. As in
the example above, sustained operation
of the unit in bridged mode with less
than 4 ohms will likely cause overheating.
If monaural operation is desired, and two
4-ohm speakers are used, it is best to
connect each speaker to an individual
amplifier output (left and right) and use
the L+R mode on the mode switch to
provide monaural operation.
The GTQ190 must not be used with
speakers that have either one of their
input terminals wired to the frame of 
the speaker or to the chassis of the 
vehicle.

(+)

(–)

(+)

(–)

GTQ 190 - English  06/03/98 11:49  Side 3

04

The low-level preamp outputs of any
radio/tape deck, CD player, or preamp/
equalizer so equipped can drive the
GTQ190. The gain controls of the
amplifier are used to match its input
sensitivity to the output voltage of the
source. This matching is important to
keep noise low and is explained in the
“Adjusting the Gain” section of this
manual (see page 11).
Thanks to Universal Interface Circuitry,
the GTQ190 can also be connected to
power amplifiers, radios or equalizers
that are equipped with only speaker
outputs by connecting them through the
speaker-level input connector. Inside the
GTQ190, the speaker-level and preamp-
level inputs are connected through a
mixing circuit, which allows them to be
used simultaneously. Therefore a low-
level source, such as a CD player
equipped with a volume control, may be
connected to the preamp-level inputs at
the same time as a powered radio/tape
unit is connected to the speaker-level
inputs. This provides a higher
performance alternative to an FM
modulator connection when you wish to
add CD capability to a factory cassette
stereo. Switching from one source to the
other is as simple as turning the desired
source on and turning the undesired one
off — no additional switches or relay
connections are needed.

The system options of the GTQ190 are
numerous. All JBL amplifiers are
designed with sufficient adjustment
range to match with the accepted normal
voltages and impedances used by
virtually all car audio components. With
very few exceptions, the GTQ190 will
match up with nearly any equipment you
already have.

The diagrams on pages 4 and 5 show the
most common basic system
configurations of GTQ amps. One or
more of these building blocks may be
combined to form elaborate system
designs. For additional ideas, refer to the
“Add-On and Upgrade Steps” section
(see page 11).
GTQ amps use the terminology “Group
1” and “Group 2” to indicate the two
main signal paths within the amplifier.
Each “group” may consist of a mono
bridged signal or a stereo pair of L+R
signals depending on the system
configuration.

GR 1

GR 1

GR 2

GR 2

GR 1

GR 2

GTQ 190 - English  06/03/98 11:49  Side 4