[Amps] Replacing 811A with 572B

[Bill Fuqua]

I don't think the amplifier will run any cooler since the efficiency will 
not improve.
The gain may be a bit lower since the 572Bs are intended for higher plate 
voltage.
But other than that there should be no problem. The tubes will take more abuse
during tuning up but may not actually last longer since that may ultimately 
be determined
by cathode emission. There is no reason for the cathodes to last any longer for
the 572Bs than the 811A..

73
bill wa4lav


At 07:58 PM 4/9/2008 -0400, you wrote:
>Why don't you think it's a good idea?
>
>The amp will run cooler, the tubes will last longer and the performance
>will be about the same. What's not to like?
>
>73,
>Scott, N9AA
>
>Bert Almemo wrote:
> > Hi guys,
> >
> > I have a friend who wants to replace 4x811A with 4x572B in an Ameritron 
> amp.
> > I don't think it's a good idea but he insists a lot of hams do it. What do
> > you think?
> >
> > 73 Bert, VE3OBU
> >
> >
> >
> >
> >
> >
> >
>
>_______________________________________________
>Amps mailing list
>Amps at contesting.com
>http://lists.contesting.com/mailman/listinfo/amps