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[AMPS] Heath SB-230

To: <amps@contesting.com>
Subject: [AMPS] Heath SB-230
From: w8jitom@postoffice.worldnet.att.net (w8jitom@postoffice.worldnet.att.net)
Date: Wed, 3 Sep 1997 22:49:39 +0000
> From:          Rich Measures <measures@vc.net>

I said:
> >It might be a good idea, before you pull out your data sheets, to 
> >read the instructions on using them. ALL through the guidelines grid 
> >power is mentioned as PEAK grid voltage times indicated grid 
> >current. 

Rich claims: 
> I have Volume I and Volume II of *Eimac TUBES*, which total over 5 inches 
> in thickness and contain specification sheets and constant current curves 
> for virtually every non-military power grid tube Eimac makes.  I searched 
> throughout, and there appears to be no such statement, Mr. Rauch - - not 
> "ALL through" or even in one place.  I find it a bit odd that you have 
> not quoted the statement, page number(s), and publication date of the 
> alleged Eimac document.

Eimac Tube Performance Computer number 5 (detailed instructions) on 
page 4 in the 1952 and 1967 paper. You can also find it printed on 
the overlay supplied to use with the curves you so often misuse.

You can also find it on page 29 of Care and Feeding of Power Grid 
Tubes, I believe Phil K5PC told you that last month.

Remember the Eimac formula is an approximation, and varies with the 
operating characteristics of the PA. Just as we can't multiply 
indicated anode current times RMS anode voltage to get anode 
dissipation, it also doesn't work with a grid. It's a long 
complicated process with the control grid, although I was 
pleased to recently learn there is software available that will do 
the calculation in a matter of seconds for popular tubes.

I think most people are smart enough to know 5 watt grids can be 
easily destroyed by improper tuning of a GG PA, despite what you 
claim Rich.

73, Tom W8JI

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