U20471 Used Ameritron ARB-704 Transceiver Amplifier Interface

U20471 Used Ameritron ARB-704 Transceiver Amplifier Interface

Overall Condition: Used, good physical and operational condition overall! Cosmetic Details: The textured black metal enclosure shows light edge rub marks and handling blemishes consistent with standard station use, with no major standout scratches or deep scuffs. The casing remains straight, square, and structurally sound. The front white graphics and red XMIT transmit indicator LED are clean and intact. Rear Ports & Connectivity: Rear-panel jacks include gold-trimmed/nickel RCA phono jacks for Amp, ALC, and Radio, a clean DIN Multi-Port socket, and a solid center-positive 12V DC Power barrel receptacle—all firm, corrosion-free, and in good condition. Offered as the interface unit only.No Cables included

The Ameritron ARB-704 is an essential protective buffer interface designed to safely couple modern solid-state amateur radio transceivers to RF power amplifiers. Modern transceivers feature delicate internal TX keying circuits (often limited to low DC voltages and currents), making them highly susceptible to damage from the high relay coil voltages, negative transients, and inductive back-EMF spikes generated by legacy or high-power amplifier switching circuits.

Engineered with high-speed, optically isolated solid-state switching, the ARB-704 completely isolates your transceiver's keying line from amplifier relay voltages up to 200 Volts and switching currents up to 200 mA. It operates virtually instantaneously (under 1 millisecond), ensuring flawless compatibility with full break-in CW (QSK), high-speed digital modes, and standard SSB operation without introducing keying relay chatter or timing delays.

Condition Breakdown

• General: Pre-owned, solid functional condition throughout with expected light station handling

• Enclosure State: Durable black steel housing is straight and undamaged; shows minor handling wear and edge rubs with no prominent gouges

• Indicator LED: Front red XMIT status lens is clean, intact, and firmly mounted

• Rear Connectors: Amp, ALC, and Radio RCA sockets are tight with clean outer shields; DIN Multi-Port and 12V DC barrel jacks are solid and undamaged

• Note: Listing is for the ARB-704 interface unit only (requires standard 12V DC power source and RCA or DIN interconnect cables)

Key Features

• Universal Transceiver Protection: Protects delicate transceiver PTT keying circuits from destructive high-voltage amplifier relay spikes and back-EMF

• High-Speed Solid-State Switching: Ultra-fast sub-millisecond response time handles full break-in QSK CW, digital data, and VOX operations effortlessly

• Wide Voltage & Current Tolerance: Safely switches positive or negative amplifier keying lines up to 200V peak at up to 200 mA

• Dual Interconnect Options: Supports universal standard RCA phono patch cables as well as dedicated pre-wired Ameritron radio interface cables via the DIN Multi-Port

• Pass-Through ALC Line: Dedicated RCA jacks allow ALC voltage feedback between amplifier and transceiver

• Front Transmit Status LED: Visual red XMIT indicator confirms keying line closure in real time

• Compact Footprint: Small, low-profile desktop enclosure tucks neatly behind station gear or under a monitor shelf

What's Included

• Ameritron ARB-704 Transceiver-to-Amplifier Interface Unit

Warranty

Comes with our 90-Day Warranty!

S/N: n/a

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