6400 and buffer box with AL80-B

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  • Updated 2 years ago
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I read the manual for my amp and was wondering if I still need a buffer interface box.

 Here is the excerpt from my Amp's manual 

"Shielded audio type cable with a standard male phono plug should be used to connect to the

"RLY" jack on the AL-80B. This jack has positive 12 Vdc open circuit and supplies 100 mA

of current when pulled to ground. The relay circuit has an internal back pulse canceling diode

to protect sensitive exciter circuits from damage"
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Posted 2 years ago

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Lou Dietrich

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"Δ – The TX Relay outputs are designed to handle signaling levels of up to +40 VDC @ 140 mA maximum.  Some amplifiers do not have circuits to prevent keying voltage transients and older amplifiers may exceed the maximum voltage level resulting in damage to the radio if directly connected.  Verify the voltage/current on your external device before connecting to TX Relay 1-3.  FlexRadio highly recommends the use of a use a buffer/isolator box between the radio and the external device as a best operating practice regardless of the keying voltage.  "

From my experience, it is always better to use an amp buffer box. I use the Ameritron ARB704 for years with all my rigs and amps. Nest insurance for minimal cost. 

73/ Regards

Lou N2TU
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Lou Dietrich

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Ria - N2RJ, Elmer

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I always used a buffer as cheap insurance. This puts optical isolation between my radio and amp. This means that if there is a short that sends high voltage through the key line it will sacrifice the $100 buffer and not my $7000 radio.