Open Box Ameritron ARB-704 SN112730

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Open Box Ameritron ARB-704 SN112730

Amplifier Interface Buffer

Please choose appropriate cable from list of related accessories.  

The ARB-704 advanced interface is compatible with all common radios and amplifiers even though radios and amplifiers do not have standardized voltages, accessory plugs, or wiring. This interface is designed to work with any amplifier/radio combination.

The input is designed to be compatible with any transmitter or transceiver, and the output is compatible with AC control lines or DC positive or negative amplifier control lines having up to 200 Volts peak open circuit voltage and 300 mA of operating current.

Why you need the ARB-704

Amplifiers can damage radios if the amplifier has too much relay control voltage, voltage spikes, or excessive current on the relay control line. Such damage often appears as "stuck" or "sticky" transmit relays in exciters or shorted transistors on transmit control lines. In most cases where the radio is damaged, the system transmits normally but the external amplifier stays locked in a "transmit" mode. This prevents receive signals from coming through the amplifier with normal levels whenever the amplifier is in the "ON" or "OPERATE" position.

The ARB-704 has many electrical advantages over conventional relay buffer systems. The ARB-704 has no moving parts, switches almost instantaneously. It is noiseless, has very long life, and will not develop dirty contacts. It operates with negative, AC, or positive amplifier relay control lines.

It works with any relay voltage(AC, positive or negative) up to 200 peak volts and any relay current up to 300 mA. The ARB-704 is fully compatible with conventional amplifier relay systems. It is especially suited for buffering vacuum relay QSK amplifiers, since the ARB-704 does not affect attack or release times in a deleterious manner.

The ARB-704 operates with transmitters or transceivers that pull amplifier control lines to ground, or output a wide range of positive or negative control voltages. The transmitter only switches currents under .35 milliamperes and very low voltages when using the ARB-704. Measures a super compact 4-1/4W x 1-3/4H x 2-1/4D inches

The ARB-704 is supplied with the following:

  • One power connector cord and plug with red wire (+12 Volts) and black wire (- and ground).
  • Three phono (RCA) cord with connectors on each end. These cables are for relay, ALC and amplifier control lines.

Check out this video from our friend, Mike, at Ameritron on "Hooking up your Ameritron Amplifier". There is a short description of how this interface buffer works, how to hook it up, and which connections are important, starting at 3 minutes 15 seconds into the video until the 6 minute 30 second mark.  But the entire video is educational, even if just as a check-list before powering on!

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