Kenwood eXcelon X503-1 Mono Class D Subwoofer Amplifier

Mono power for your subwoofer

The X503-1 is a single-channel Class D amplifier from the Kenwood eXcelon line. Kenwood rates it at 300 watts x 1 RMS at 4 ohms and 500 watts x 1 at 2 ohms, with 1,000 watts maximum. Its CTA-2006-D rating is 300 watts at 4 ohms and 1% THD or less, with an 85 dBA signal-to-noise figure. Frequency response runs from 20 to 200 Hz, and the amp is stable with speaker loads from 2 to 8 ohms.

Bass tuning controls

A variable low-pass filter sets the crossover from 50 to 200 Hz at 24 dB per octave. The infrasonic filter switch cuts the inaudible frequencies below 25 Hz, which helps the amplifier and subwoofer work more efficiently. Bass boost adds 0 to 18 dB at 40 Hz, and input sensitivity adjusts from 0.2 to 5.0 volts for RCA inputs and 4 to 12 volts for speaker-level inputs. The included wired remote sets the bass level from the driver’s seat.

Built for easy installs

All power, speaker and input connections sit on one side for tidy wiring. The included speaker-level input harness and signal-sensing turn-on let the amp work with a factory radio that has no RCA outputs. Set-screw terminals take 4 to 6 gauge power wire and 8 to 16 gauge speaker wire, two 30 A fuses protect the circuit, and a resin terminal cover is fitted. The output coil has a magnetic shield and PMLCAP capacitors are used in the filter circuit. The amp measures 8-3/8 x 2-1/16 x 5-7/8 inches and weighs 3.3 pounds.

• eXcelon Class D mono amplifier designed to power one or more subwoofers
• Rated 300 watts x 1 RMS at 4 ohms and 500 watts x 1 at 2 ohms
• CTA-2006-D compliant: 300 watts at 4 ohms and 1% THD or less, 85 dBA
• Variable low-pass filter from 50 to 200 Hz at 24 dB per octave
• Infrasonic filter switch cuts frequencies below 25 Hz for cleaner, more efficient bass
• Bass boost control adds 0 to 18 dB at 40 Hz
• Speaker-level input harness and signal-sensing turn-on included for factory radio upgrades
• Wired remote bass level control included so you can adjust the sub from your seat
• One-side connections with set-screw terminals and two 30 A fuses

• Power and ground wiring, an inline fuse, RCA cables and speaker wire are not included.
• The amplifier draws up to 28 A; use 4 to 6 gauge power wire as Kenwood specifies.
• Speaker impedance is 4 ohms, with 2 to 8 ohms allowable.

• Kenwood eXcelon X503-1 amplifier
• Speaker level input cable
• Wired remote controller
• Remote cable
• Self-tapping screws 4 x 16 mm (4)
• Hexagon wrench 2.5 mm
• Hexagon wrench 4.0 mm
• Washer
• Hex nut

• Kenwood X503-1 instruction manual (PDF, English/French/Spanish; shared with KAC-531)