[Amps] A 3-500Z question...

[R.Measures]

On Sep 1, 2004, at 1:52 PM, Kim Elmore wrote:

> While idly thinking the other day, I began to wonder why no one builds 
> grid-drive 3-500Z amps. I know the tube was designed for GG service, 
> but that doesn't preclude grid-drive service.

For non-linear operation, a high-Mu triode may be grid driven.  
However, for linear operation with a grid driven triode, only a low Mu 
will do.  The reason why can be seen by looking at the characteristic 
curves for a 3cx3000A1 and a 3CX3000A7.
  --  note --  virtually zero grid current can be allowed to flow in 
grid driven linear service.

>  Eimac even specs grid-drive service on the data sheet. Is 
> neutralization a big pain for them?  Or, is the result not worth the 
> effort given the variety of high-quality tetrodes available?

Without neutralization an 8171 or 8170 typically get squirrelly above 
20MHz.
>
> Kim Elmore, N5OP
>                           Kim Elmore, Ph.D.
>                        University of Oklahoma
>         Cooperative Institute for Mesoscale Meteorological Studies
> "All of weather is divided into three parts: Yes, No, and Maybe. The
> greatest of these is Maybe" The original Latin appears to be garbled.
>
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>
Richard L. Measures, AG6K, 805.386.3734.  www.somis.org