04
Signal Sources
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.
Other Components
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.
Typical Applications
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.
–
+
L+
L–
R+
R–
L–
R+
–
+ –
+
R
L
R
L
R
L
–
+ –
+
L+
L–
R+
R–
L+
L–
R+
R–
–
+ –
+
GR 1
GR 1
GR 2
GR 2
R
L
R
L
R
L
R
L
R
L
R
L
GR 1
GR 2
R
L
R
L
GTQ 190 - English 06/03/98 11:49 Side 4
