[Amps] 3cx1500D7 vs. 3cx1200A7

[R.Measures]

•  the filament has the same V and I as 2, 3-500Zs.

>Why to make a 3cx1500D7 to replace two 3-500z ?
>One 3cx1200A7 (it is already on the market) can give the same power of a 
>couple 
>of 3-500z. 
>I am not able to understand the reason to make a tube (3cx1500D7) wich gives 
>about 200 watts more than a 3cx1200A7. 
>
>Paul i8ixo
>
>
>
>_______________________________________________
>Amps mailing list
>Amps at contesting.com
>http://lists.contesting.com/mailman/listinfo/amps
>