Yes, feed trough power should be subtracted for the real calculation.
To me it looks as Eimac did not do that on their 3CX3K datasheet.
My glass envelope tubes can be driven very hard in GG without getting bad
IMD figures.
I do 4 times the factory claimed dissipation into the dummy load but I guess
there data is very very conservative.
73
Peter
-----Original Message-----
From: Bill Fuqua [mailto:wlfuqu00@uky.edu]
Sent: Mittwoch, 23. Juli 2008 22:28
To: Peter Voelpel; amps@contesting.com
Subject: Re: [Amps] Bill Orr comment
Many of the old spec sheets indicate a correction for plate tank losses.
Also, when figuring class AB2 efficiency don't forget the feed-thru power
for grounded grid amplifiers.
My 4-1000A amplifier when heavily driven will do almost 2.5 times spec.
plate dissipation into a dummy load.
But it is a grounded grid amplifier and I don't EIMAC ever actually
specified Grounded data for these tubes. But, Bill Orr did list some
information of his own in the "Radio Handbook".
73
Bill wa4lav
At 01:10 PM 7/23/2008 -0400, Peter Voelpel wrote:
>2-2.5 times the dissipation is normal.
>Assume 1500 out, at 70% efficiency that is 643W dissipation, 1500/643=2.33.
>Eimac claims 75% efficiency on their 3CX3000A7 datasheet in AB2.
>
>73
>Peter
>
>-----Original Message-----
>From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com]
>On Behalf Of Gudguyham@aol.com
>Sent: Mittwoch, 23. Juli 2008 18:30
>To: amps@contesting.com
>Subject: [Amps] Bill Orr comment
>
>I was reading the Bill Orr handbook and on his section about amplifiers
>he says.....A properly designed grounded grid amplifier should produce
>2 to 2.5 times the plate dissapation of the tube in output. He did
>not put any limitations on the statement as to IMD or anything like
>that. He did not say if the tubes ratings would be surpassed (I am
>sure they would), but I think what he was saying is that the tube
>should continue to make power to 2 to 2.5 times it's dissapation
>before it would not make any more power and flatten out.
>
>Upon speaking with an amp "Guru" about this subject, he procalimed that
>Bill Orr was a "QUACK". The basis of his claim was that he was never
>able to build an amplifier that obtained that kind of results.
>What say you? Lou W1QJ
>
>
>
>**************Get fantasy football with free live scoring. Sign up for
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