Stereo Amplifier XJ-300ST

The XJ-300ST maintains characteristics of the small unimposing, connectable design while still packing all the power and flexibility that made the XJ-300FR so popular.

Keeping flexibility and spatial convenience in mind, Earthquake has kept their patented EQ Interlock design so that two amplifiers can be clicked together resulting in a 4-channel amplifier while only using 1U of rack space. The small size of the XJ-300ST is made even more convenient by its unbelievable amount of cool running power. Approaching 99% efficiency the XJ amp never gets hot, allowing it to be placed in tight rack surrounded by other components.

Endless configuration scenarios allow the XJ-300ST amplifier to be used as a mono (bridged) amplifier, 2.1 channel amplifier, 2-channel amplifiers 4/8/12 and 16-channel amplification with industry leading power density and efficiency.

To make the XJ-300ST even more user friendly than it already is, a 12V trigger has been added to the amplifier. This 12V trigger allows the user to power the amplifier through an outside source.

At only one rack U high and half a rack in width, plus the installation options makes this compact, versatile class J amplifier the go to amp for installers.


  • Class J stereo modular design provides cool running power
  • Its compact and unimposing size makes it an installer’s go-to amplifier
  • Numerous application possibilities with customizable channel setup
    • Allows for mono bridged, 2-channel, and 2.1-channel wiring configuration
    • Versatility allows for multi-channel audio systems
  • Proprietary Interlocking Design
    • Used for joining two XJ-300STs for side-by-side rack mounting
    • 1U rack space tall with half-rack width chassis
  • Signal sensing toggle switch with +12V trigger input
  • Selective variable crossover
  • Bypass/lowpass toggle switch
    • Turns crossover on or off
  • 0–180° phase adjustment
  • 110V/220V AC selector
  • RCA inputs
  • Volume control
  • 4 detachable short rack ears included
    • Used for both rack and wall mounting
  • Back bracket included
    • Links multiple XJ-300ST amplifiers
Output Power2 x 110 WRMS @ 8-Ohm
2 x 170 WRMS @ 4-Ohm
170 WRMS @ 8-Ohm Mono Bridged
300 WRMS @ 4-Ohm Mono Bridged
Frequency Response20Hz–20kHz
Input Impedance10 kOhm
Impedance4–8 Ohm
Crossover Frequency50Hz–160Hz
S/N Ratio> 97 dB
Damping Factor> 400
THD< 0.08%
Compact size (W x H x D)8 ½” x 1 7⁄8″ x 8″
In the Box
1x XJ-300ST Stereo Class J Amplifier
4x Short Mounting Ears
(Mounting screws included)
1x Back Bracket
(Mounting screws included)
4x Rubber Feet
1x Power Cord