[TenTec] Problem with Orion 2 driving an Ameritron 811H Linear

[Tom]

I have found that my Orion 2 (w/ model 709 TT mike) will drive my linear to a max. output of 300 watts while providing 40 watts of drive. My IC765 (w/ the model SM20 mike) will drive the same linear with 35 watts to an output of 500 watts. I have switched coax leads, etc. to try to account for bad hardware, etc.

As per suggestions from TenTec, I tune the rigs and adjust the linear settings using only the CW mode, tried some compression, adjusted the mike gain and even increased the 
TX EQ (from zero to -12 ) and nothing increased the ability of the Orion 2 to provide more than a max. output of 300 watts. Meanwhile, the "good old" IC765 cooks along yielding 500 watts for a drive of 30 watts. What 'am I overlooking? The only variable I can see is the rigs/mikes. Has anyone run into a similar problem or do you have any suggestions as to what I should try next?

Will appreciate any input you could provide.

73,  Tom N3XQ