Guide to Amateur Radio Amplifiers 2026: Part 4, 4O3A Power Genius XL Amplifiers

4O3A produces amateur radio equipment that’s built to perform, built to last, and built for hams looking to seriously upgrade their capabilities.

Case in point—the company’s solid-state Power Genius Amplifiers. They deliver 1,500W-plus of output across the 160-6M bands using dual NXP MRF1K50H LDMOS transistors, each rated for 1.5 kW. Users can expect high headroom, low IMD, clean signal output, and a host of other benefits.

4O3A Power Genius XL Amplifiers come in two versions: the SO2R model with true SO2R capability, offering 70 dB of isolation between two inputs; and the 3X1 version that features a 3-to-1 antenna switching module, allowing you to connect three antennas to a single radio.

DX Engineering is the exclusive U.S./Canada distributor of 4O3A amplifiers, Tuner Genius XL Antenna Tuners, the Antenna Genius 8×2 Plus Antenna Switch, and other equipment. Find the full lineup of 4O3A products available at DX Engineering here.

How do DX Engineering customers describe their 4O3A Power Genius Amplifiers? As one satisfied user said, it’s “bullet proof,” “built like a tank,” “and your last amp for sure.”

We’ll let Michael, a DX Engineering customer, go into more detail in his five-star review at DXEngineering.com:

“I finally got my hands on the 4O3A Power Genius XL HF/6M SO2R amplifier after waiting over a year, and man, it was worth every second of the anticipation. Paired with my FLEX-8600, This thing integrates like it was made for it—seamless LAN control means band changes, PTT, and power levels sync up automatically without any fiddly cables or manual switching, turning my station into a contest-ready powerhouse from barefoot FT8 to full 1,500W+ blasts across 160-6 meters.

The solid-state design runs cool and consistent, pumping out legal-limit power with a touchscreen that’s intuitive for quick tweaks, and those four SO239 ports make SO2R a breeze for my skyloop and dipole setups. I’ve been running FT8 profiles at 500W steady with no distortion or heat issues, and it handles my high-power antenna feedline perfectly, even with the tuner on deck next. Couldn’t be happier—rock solid build, zero glitches, and it just elevates the whole Flex experience. If you’re on the fence, don’t hesitate; I’d buy it again in a heartbeat and I’m already eyeing the matching Tuner Genius XL to complete the stack.”

Other features of the 4O3A amplifiers include:

• Ultra-fast SWR protection (<1 µs), over-temp, over-voltage, over-current
• Integrated MEffA (Maximum Efficiency Algorithm) that dynamically adjusts DC voltage for optimal efficiency
• Thermostatically controlled Smart Fans with high-efficiency heatsink
• Duplexed filters maximize harmonic suppression and efficiency
• CAT, band decoder, LAN interface for operation with other exciters
• Large touchscreen for local control and future upgrades
• Seamless integration with FlexRadio systems via SmartSDR
• Works with third-party transceivers through Ethernet, RS232, CI-V, and BCD interfaces.
• Support for remote operation via SmartSDR, Windows, and Android apps
• Measures 14.1″ x 6″ x 20″ and weighs 37.48 lbs.
• Input Voltage: 90-250VAC, 50/60 Hz*
• Power Supply: Internal Modular/ Switching
• Max A/C Current: 15A @ 220VAC or 120 VAC.

*220 VAC supply and 20A minimum required for full power. Maximum of ~750W when using the 180VAC or less.

NOTE: These amplifiers are shipped without a power connector on the end of the power cable. Customers are urged to work with their electrician to finalize AC power delivery.

Also find 4O3A amplifier accessories, including a rack mount shelf for the PGXL, 3:1 coaxial power splitter/combiner, radio switches, and more at DXEngineering.com.

Check out other OnAllBands posts covering amplifiers we’ve showcased, including ACOM, OM Power, and the Icom IC-PW2.

And be sure to read “I’ve Got the Power. What Else Do I Need?” for insights into other upgrades you’ll need to consider when adding a high-power amplifier to your station.

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