FT-840

[ki4jxn]

I am running a FT-840 through an old Dentron 160-10l amplifier. The output of the 840 is full 100w with the the relay unplugged and the amp not keyed up. The amp does not have "standby" so I unplug the ameritron ARB-704 relay so the amp will not key up. The problem occurs when keying the amp the max power output is only 50W. Apparently there is a high impedence situation occuring in the amp circuitry causing the 840 to reduce the output power. With 50W drive I am getting just under 600w output from the amp. Any ideas on the cause of this and what to check so I can get my drive power up? What can cause a high impedence situation in a tube amp? I don't have any experience with working on tube amps so any advice is helpfull. I have opened the case for inspection and did not observe anything obvious causing the situation.
Thanks,
73
KI4JXN

[KD5LWU]

With many Amps if the input power is too high it will throttle the output power of the Amp. Many amps only require 10-15 watts input for maximum output of the Amp. Let us know what you discovered. 73 Johnny KD5LWU Forum Admin