Infinity Reference REF-551A Mono Subwoofer Amplifier

Infinity Reference REF-551A Mono Subwoofer Amplifier
(JBL Infinity REF551A)

We Think You Should Know

• Australian Infinity Warranty
• Purchase Guarantee (see T&C's)
• 550W RMS at 2 ohms
• 370W RMS at 4 ohms
• 10Hz – 320Hz frequency response
• Variable bass boost and subsonic filter
• Phase control for system integration

Overview

The Infinity Reference REF-551A is a mono subwoofer amplifier engineered to deliver powerful, dedicated low-frequency amplification for car audio systems. With 550W RMS at 2 ohms and 370W RMS at 4 ohms, this Class A/B amplifier provides ample power for demanding subwoofer installations. The 10Hz–320Hz frequency response ensures deep, accurate bass reproduction, while variable bass boost, subsonic filter, and low-pass filter allow precise tuning. Phase control optimises subwoofer integration with existing speakers, making this compact amplifier ideal for enthusiasts seeking authoritative bass performance.

Key Features:

• 550W RMS at 2 Ohms – Delivers powerful, dedicated bass amplification for demanding subwoofer installations, with 370W RMS at 4 ohms for flexible system matching.
• 1300W Peak Output – High peak power capacity provides dynamic headroom for impactful transient response and authoritative bass impact.
• 10Hz – 320Hz Frequency Response – Wide sub-bass range captures the deepest low frequencies for accurate, immersive bass reproduction.
• Class A/B Amplification – Traditional Class A/B design delivers clean, musical sound with low distortion and natural sonic character.
• Variable Bass Boost Control – Adjustable bass boost allows customisation of low-frequency output to match listening preferences and enclosure characteristics.
• Subsonic Filter – Removes ultra-low frequencies below the audible range to protect subwoofers and improve overall system efficiency.
• Variable Low-Pass Filter (LPF) – Adjustable crossover ensures seamless integration with main speakers, directing only the appropriate frequencies to the subwoofer.
• Phase Control (0-180°) – Adjustable phase alignment ensures optimal subwoofer integration with existing speakers for coherent, well-timed bass response.
• Compact Chassis Design – Measuring just 238 x 185.5 x 55.75 mm, this amplifier fits in tight installation spaces while delivering powerful performance.

Ideal For

• Car audio systems requiring dedicated subwoofer amplification
• Drivers seeking powerful, clean bass from a mono amplifier
• Systems needing flexible tuning with bass boost, subsonic, and low-pass filters
• Installations where compact chassis size is essential
• Enthusiasts wanting phase control for seamless subwoofer integration

Infinity Car Audio

Since their beginnings in 1968 Infinity Loud Speakers have been renowned for producing some of the best home and car audio speaker systems money could buy and the latest Kappa Series of speakers is no different. Infinity holds many US patents for their speaker designs and technologies from their Plus One cone technologies and true 4-ohm topology through to their exclusive Intermount, I-Mount and Starfish speaker mounting systems. Infinity is truly one of a few genuine speaker brands and a brand we have no hesitation in recommending should you have not heard of them before.

• 1 x Infinity Reference REF-551A mono subwoofer amplifier
• 2 x Spare fuses
• 2 x RCA adapters
• 1 x Quick-start guide