Glen Zook wrote:
> If you are getting almost half of the full legal peak power from a DX-100 on
> AM then your are grossly exceeding the specifications of the 6146 final
> amplifier tubes.
>
> Although Heath specified an input carrier power of 160 watts for the DX-100,
> this is definitely in excess of the RCA specifications for the 6146 or the
> 6146A/8298. MAXIMUM input power ICAS to a single 6146 when used for Class
> "C" AM phone operation is 67.5 watts and therefore a pair should not exceed
> 135 watts carrier. Assuming an efficiency of 60% then you should not see
> more than 81 watts output for the carrier. Even at 65% efficiency you should
> not see more than just under 88 watts output for the carrier. Then assuming
> the 4 times peak power output at 100% modulation, that means that you should
> not see more than 324 watts peak output at 60% efficiency or more than 350
> watts output at 65% efficiency.
>
> The life of the 6146 will be greatly extended if you drop the maximum input
> power to no more than 120 watts and even more if you drop the input power to
> around 100 watts. This means a carrier output power of 72 watts at 60%
> efficiency and 78 watts at 65% efficiency at 120 watts input or 60 watts
> carrier output at 100 watts and 65 watts output at 65% efficiency.
>
> Frankly, the station on the other end won't know the difference at 120 watts
> input and probably won't know the difference at 100 watts input. However,
> the final amplifier tubes definitely will be able to tell and the life of the
> final tubes will be much longer.
>
>
My RCA tube manual says (for 2 tubes ICAS) 600 volts Vp, 214 ma Ip, Po
104 watts! As you state in your
article on 6146 series tubes, the 6293 is mo better in this application.
73, Roger
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