Wiring, Signal Sources, Ground Wire | JBL GTQ240, GTQ360 manual

Parallel Wiring

(+)

2 ohms
Nominal	4 ohms	4 ohms
Impedance

(–)

Series Wiring

(+)

4 ohms

8ohms Nominal Impedance

(–) 4 ohms

3.2 Signal Sources

The low-level preamp outputs of any radio/tape deck, CD player, or preamp/ equalizer so equipped can drive the GTQ360 or GTQ240. 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.

Thanks to Universal Interface Circuitry, the GTQ360 or GTQ240 can also be con- nected to power ampliﬁers, radios or equalizers that are equipped with only speaker outputs by connecting them through the speaker-level input connec- tor. Inside the GTQ360 and GTQ240, 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 con- trol, may be connected to the preamp- level inputs at the same time as a pow- ered radio/tape unit is connected to the speaker-level inputs. This provides a high- er performance alternative to an FM mod- ulator 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 connec- tions are needed.

4. Wiring

4.1 Wiring

Proper wiring of the GTQ ampliﬁers and the associated components is extremely important for proper performance and long-term reliability. Using the proper type of wire is very important.

Route the wiring through the car carefully. Do not allow wires to lay against sharp sheet metal edges or any other surfaces that might wear away or cut through the insulation of the wire. Use insulated strain reliefs, rubber grommets and plastic tub- ing to protect the wires whenever they are run through sheet metal panels or are placed where they might be pulled or damaged.

4.2 Ground Wire

•Proper grounding is extremely impor- tant. Use a heat- and oil-resistant stranded copper automotive wire equivalent to the size used for the +12V connection. Crimp or solder and insulate any wire-to-wire connections. Keep the ground wire as short as possible. A ground wire must be solidly connected to a major sheet-metal structure of the vehicle such as a panel near the amp-mounting location. Scrape all paint and primer off the sheet metal at the grounding point to ensure a good electrical connection. Attach the wire to the grounding point with a nut, bolt and star washer. The high current demanded by high-powered ampliﬁers requires a more secure ground than the typical sheet-metal screw will provide. Coat the connection with silicon sealant for better long-term reliability.

4.3 Remote-In/Out Connection

•The remote power control system turns the GTQ ampliﬁer off when not in use to prevent discharging of the vehicle’s bat- tery. Because the JBL GTQ ampliﬁers include Common Sense 2-way turn-on, when using the speaker-level inputs with a head unit that includes a BTL power amp it is not necessary to connect the remote wire. The ampliﬁer will automati- cally activate whenever you turn on the head unit. If you are using the line-level inputs, or the speaker-level inputs with a head unit that does not have a BTL power amp, use the following remote wire con- nections.

•Using the REM-IN feature – When +12 volts is applied to the remote IN/OUT ter- minal the ampliﬁer is turned on. A red LED on the top panel of the ampliﬁer will illuminate to indicate the ampliﬁer is on. If the head unit has a +12 volt automatic antenna or ampliﬁer remote activation wire, connect it to the REM-IN/OUT con- nector on the GTQ ampliﬁer. When the ampliﬁer is turned on, there is a time delay of several seconds (longer in cold weather) before the ampliﬁer will produce sound. This eliminates the chance of annoying noises produced by the radio or signal processors being ampliﬁed and passed to the speakers when the system is ﬁrst activated.

•Some head units have no automatic antenna or power amp activation wire. Others have automatic antenna wires that are “on” only when the radio is used but not when a tape is played. In such cases, connect the remote-in turn-on terminal to an unused accessory terminal in the fuse block, or any other +12 volt source that is turned on and off with the vehicle’s igni- tion switch. The remote on/off system

GTQ240, GTQ360 specifications

The JBL GTQ360 and GTQ240 are part of JBL's esteemed lineup of car audio systems, designed to deliver unparalleled sound quality while ensuring robust performance tailored for automotive environments. Both models stand out for their blend of advanced technology, durable construction, and user-friendly features.

The JBL GTQ360 boasts a peak power handling of 360 watts, making it a powerhouse in sound output. This model is equipped with a 12-inch subwoofer that utilizes a high-strength polypropylene cone, allowing for deep bass response and clarity across a range of frequencies. The GTQ360 also features an oversize voice coil that enhances thermal dissipation, promoting longevity and consistent performance even during extended listening sessions.

On the other hand, the GTQ240 is slightly more compact, with a peak power handling of 240 watts. This model features a 10-inch subwoofer, designed for those who prefer a smaller footprint without sacrificing sound quality. Like its larger counterpart, the GTQ240 utilizes a durable polypropylene cone, providing durability alongside exceptional sound reproduction. Its efficient voice coil design also ensures that users enjoy a rich audio experience without unwanted distortion.

Both models employ JBL's signature technologies, including a low-pass crossover that allows users to fine-tune the subwoofer's output according to their preferences and the acoustic characteristics of their vehicle. This capability means that whether you’re a fan of thumping bass or more subtle low-end frequencies, these subwoofers can accommodate your taste.

Installation is straightforward, thanks to the user-centric design of both the GTQ360 and GTQ240. They come with adjustable mounting options and provisions that enable easy integration into various vehicle types. The construction of both subwoofers is robust, featuring a reinforced basket designed to mitigate vibration and resonance, thereby maintaining the purity of the sound produced.

In summary, the JBL GTQ360 and GTQ240 are compelling choices for car audio enthusiasts seeking superior sound quality. With their impressive power handling, innovative technologies, and durable construction, these subwoofers are set to enhance any vehicle's audio system, allowing users to enjoy their favorite music with a depth and clarity that only JBL can offer. Whether you want a powerful bass experience or a balanced sound profile, these models deliver a remarkable listening experience.