Item# GTO-504EZ



640-watt, four-channel amplifier
$199.95 each


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Finally, high-performance amplifiers that are easy to install and calibrate. The JBL® GTO-504EZ multichannel car audio amplifier provides unmatched ease of installation, configuration and calibration – processes that are necessary to produce clean, powerful sound. Whether you’re upgrading an OEM (original-equipment manufacturer) audio system or installing an aftermarket system, this amplifier offers virtually limitless applications with wired or auto-sensing turn-on – without making you fuss with adding third-party adapters or converters. These amps drive up to 15 volts of audio signal right to the inputs with either line-level or speaker-level signals. And they come with RCA-to-bare-wire adapters and a setup CD. Experience the clean and powerful output of GTO Series amplifiers in a variety of channel configurations and power ratings, all of which are CEA®-2006A compliant and backed by the JBL reputation for top quality.

What's in the box?

  • (1) GTO Subwoofers Amplifier
  • (1) Setup CD
  • (4) Bare Wire-to-RCA adapters
  • (1) Owners Manual

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General Specifications

Grand Touring

Audio Specifications

Number of Channels/Type
4-Ohm Power Output
50W RMS x 4 channels at 4 ohms, 14.4V DC, less than 1.0% THD
Frequency Response
2-Ohm Power Output
75W RMS x 4 channels at 2 ohms, 14.4V DC, less than 1.0% THD
Maximum Current Draw
Peak Power
Signal-to-Noise Ratio


640 watts (max) delivered to four channels of power

The GTO-504EZ four-channel model features 4x50 watts RMS (640 watts max). It has selectable high-pass/low-pass active crossovers and bridgeable channel pairs for total flexibility. Use this amplifier to upgrade from four channels of built-in head-unit power in an aftermarket system, as a building block in a growing system design or, by bridging both channel pairs, as a more powerful amplifier for premium component speakers.

Easy setup and adjustment of input gain

The GTO-504EZ amplifier includes an input-level switch, a setup CD with test signals and LED indicators to tell you when the setting is correct. Simply set the switch, turn the input-level knob and watch for the green light that indicates that the setup is perfect. That’s all there is to it. There’s a reason why the amplifier’s model number contains EZ. This feature significantly reduces installation time and delivers excellent results.

Wired or auto-sensing remote turn-on

JBL engineers have configured the JBL GTO-504EZ amplifier to turn on with a wired input (as in aftermarket systems) or with an auto-sensing circuit that activates whenever the amp detects an audio signal. The auto-sensing feature is helpful when you’re upgrading OEM audio systems that don’t include a remote trigger wire. It’s easily defeated by a switch when you’re using a wired remote turn-on input.

Input signal up to 15 volts (line-level or speaker-level)

The GTO-504EZ amplifier accepts a wide range of inputs up to 15 volts with line-level or speaker-level signals. Using RCA-to-bare-wire adapters included with the amplifier, you can connect to virtually any OEM or aftermarket audio system. The end result is an amplifier that works with the widest range of cars on the road.

Built-in, variable active crossovers

Active 12-decibel/octave low-pass crossovers offer variable filter points between 40Hz and 280Hz. You can select high-pass (HP) filtering, low-pass (LP) filtering or OFF. Importantly, all filter points on the adjustment dial match the silkscreened frequency points on the amplifier chassis – a feature that not all amps provide.

Built-in, variable bass boost

The GTO-504EZ provides a range of bass boost from 0 decibels to +12 decibels, centered at 45Hz. This is a useful feature for restoring some bass that may be limited by the low-frequency response of certain speakers in the system – or to enhance a particular range of bass that the speakers already produce well.

Bridgeable channel pairs

Pairs of the GTO-504EZ system amplifier’s main channels can be bridged into a single, more powerful channel. This setup is useful for flexible audio system designs in a growing syste or for full-range speakers in a system that needs more power.

Automatic thermal and low-impedance protection

Amplifier protection is just like insurance; you hope you’ll never need it, but it’s sure nice to have when you do. Thermal protection keeps the GTO-504EZ system amplifier from overworking itself to the point of premature failure. Low-impedance protection keeps the amplifier safe from any speaker or wiring failures that result in short circuits.

Warranty 1 Year Warranty

Products purchased online or from an authorized local retailer and under warranty may qualify for an exchange with a valid receipt.

Purchases made from an unauthorized dealer will not be elibible for exchange.

Request an Exchange

Product Support

Call us: 1.800.336.4525

  • Sales and pre-sale assistance
  • Technical help
  • Parts and accessories


GTO-504EZ is rated 4.5 out of 5 by 2.
Rated 5 out of 5 by from Great Value, Great Sound I have been running this amp paired with the GTO 3EZ for about a year now. I initially set up the amps to take a high level speaker input but then later included a digital sound processor and I switched to the low-level inputs. Having used it in both configurations, I can say this is a great full featured amp. The crossover and gain settings are accurate and a breeze to set up. The sound is great with plenty of headroom and the units look sharp. The layout of the amps makes it easy to tweek the settings to get things just right, which I found helpful in getting the right sound from the system. I'm a JBL fan now!
Date published: 2014-09-29
Rated 4 out of 5 by from Small size but great sound! To be honest I was skeptical about this one. I was always used to big amps, when I got t his this one I was like is this gonna be enough? But once I installed it, it was pretty awesome. I can't say it is the best out there. But it is good sounding amp. Loud enough to get your ears ringing for while. But not just loud minimal distortion good sound quality. I am using JBL P660C component speakers with it. Good match
Date published: 2013-07-14
  • 2015-08-30T08:24CST
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