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Old 11th September 2009, 06:08 AM   #11
Yvesm is offline Yvesm  France
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Roughly as a R loaded driver for a 813:

B+ = 400V
RLoad = 5K3
Ia0 = 35mA
Ua0 = 175V
Vg1 = -3.3V

more than 270V pk to pk oputput swing for +/- 1.5V pk to pk input.

my two pence.

Yves.
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Old 11th September 2009, 11:17 AM   #12
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hey-Hey!!!,
Now drop Vg2 so its g1=0 line matches the -2.5V line for the family of curves at the higher Vg2. Less g2 current would be a pleasant side-effect.
cheers,
Douglas
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Old 11th September 2009, 05:51 PM   #13
nhuwar is offline nhuwar  United States
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Thanks guys you have been a big help.



Nick
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Old 12th September 2009, 08:13 PM   #14
nhuwar is offline nhuwar  United States
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Hey Douglas,

Did you try a 813 at a 40% ul tap? If yes how did it work?

Or is 20% the only way to go?


Thanks,
Nick
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Old 12th September 2009, 08:52 PM   #15
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Quote:
Originally Posted by nhuwar View Post
Hey Douglas,

Did you try a 813 at a 40% ul tap? If yes how did it work?

Or is 20% the only way to go?


Thanks,
Nick
hey-Hey!!!,
It worked very well, save for making about half the power. The low B+, minus 40% of the plate swing lowers the g1=0V line too far so swing w/o grid current is small. At 30% the envelope to work under is far larger, and I suspect 20% might just be better...soon enough, eh?
cheers,
Douglas
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Old 12th September 2009, 08:56 PM   #16
nhuwar is offline nhuwar  United States
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Ok I'm thinking I will try it with the 40% tap first then. I can always reverse the leads if I want to try it at 20 too.



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Nick
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