ST900 Rockford Fosgate PBR Motorcycle Amplifier


This top end, powerful motorcycle amplifier by Rockford Fosgate pushes over 900 peak watts (400 RMS watts) and features full-range sound designed for compact systems.  This efficient amp is available in a 2-channel (PBR300X2) or 4-channel (PBR400X4D) option and packs a Punch in motorcycles, ATVs and other power-sports vehicles without sucking a lot of juice from your electrical system.


○ Connection:  RCA/headphone (or add on a Bluetooth controller
○ Impedance:  4-Ohm or 2-Ohm Stable
○ Crossover:  LP/AP/HP Switched Crossover
○ Crossover Slope:  12dB/Oct Butterworth
 Amplifier dimensions: 1.53 x 4.25 x 6.75 inch

 Wiring: Speaker Wire and RCA Input Harness Included (Power Wiring Kit Available)
 Warranty:  One-Year Warranty
 Manufacturer Model:  PBR300X2 (2CH) or PBR400X4D (4CH)

2-Channel Amplifier (PBR300X2)

○ Peak Wattage:  Over 900 Peak Watts of CEA-2006 certified power
○ RMS Wattage
:  150 Watts RMS x 2 (2-Ohm) / 100 Watts RMS x 2 (4-Ohm) / 300 Watts x 1 (4-Ohm Bridged)

○ Crossover Frequency:  LP/AP/HP 50 - 500Hz
○ Circuit Topology Class: Class BR

4-Channel Amplifier (PBR400X4D)

○ Peak WattageOver 950 Peak Watts of CEA-2006 certified power
○ RMS Wattage:  
100 Watts RMS x 4 (2-Ohm) / 50 Watts RMS x 4 (4-Ohm) / 200 Watts RMS x 2 (4-Ohm/Bridged)

○ Crossover Frequency:  Selectable HP @ 60Hz or 80Hz / AP / Fixed LP @ 80Hz
○ Circuit Topology Class: 
Class D




Ask a Question
  • What size power and ground do I need for st900 amp or is it included?

    The complete ST900 motorcycle speaker system includes the RF wiring kit.  For the amp purchased seperately, we recommend the RFK10 wire kit from Rockford Fosgate.

  • Can this amp be mounted in the fairing of a 2000 H-D Roadglide? What is needed to be mounted there?

    This amp can be mounted rigfht on top of the radio in the fairing.  We offer special mounts for this purpose.

  • Will this amp fit under the fairing of a stock 2018 street glide special?

    Yes, it is designed to mount right on top of the radio in the fairing.

  • Interested in the ST900 amp for a '17 H-D Street Glide Special. Is this a plug n' play type set up or do I need a adapter harness?

    The amp connects to a power and ground connection and then connected to the speakers.  It is a fairly straight forward install with instructions provided.  We also offer adapter harnesses to make it easier but these only cover '96 - '13 model years.

  • What are the recommended saddlebag speakers for the ST900 amp with my original Harley-Davidson bags?

    We recommend the Polk Audio DB692 DB+ Series 6x9 speakers for the saddlebag lids.  These are waterproof and perform very well with our ST900 motorcycle speaker system.

  • Will the ST900 Amplifier handle 2ohm and/or 4 ohm speakers?

    The ST900 Rockford Fosgate amplifier supports both 2 ohm or 4 ohm speaker configurations.

  • I have front speakers and back speakers on my bike. I'm interested in the ST900 amplifier .... can the loudness be changed for the front and back for instance have the back speakers louder than the front speakers

    Yes, the gain can be adjusted separately for the front and the rear channels... as well as the variable crossover (EQ).

  • Will my Bluetooth controller that came with the st-600 plug into this amp?

    This amp will only work with the MTX handlebar controller (or similar) that is included with the ST600 system.

  • Can this amp be placed inside of the saddle bag?

    Yes, the saddlebag is one of our recommended locations.

  • What is the recommended gain setting for the ST900 speakers

    We like to push our speakers to their full capability, so typically around 9 or 10 with crossover set to HP or AP.

  • How much is a Bluetooth controller for this amp?

    We offer 2 Bluetooth controller options for the Rockford amplifier.  They are priced at $39.99 and $99.95 depending on what features you want.  You can see them both here:

  • Does this amp come with the wiring hardware or do you have to buy that separately?

    All wiring hardware is included standard with the amplifier.  This product also includes the wiring kit for power, remote and ground connections.

  • Can 2 of these amps be used from the same bluetooth device simultaneously ? I would like to run 2 amps from the same bluetooth source that you sell.

    Yes, you could use a headphone splitter from the Bluetooth controller and connect to 2 seperate amplifiers.

  • Is this a 4 channel amp or 2 channel amp?

    It is a 4-channel amplifier.