Bill Orr was hardly a quack. Very knowledgeable and nice guy, met him
several times over the years. An 8877 will get pretty darn close to 2 X. It
was used in at least one 2.5 KW commercial FM transmitter that I know of and
by FCC rule the transmitter had to be capable of 110% rated power (2750W).
And that is CCS!
73's
Chuck
W6RD
----- Original Message -----
From: <k9mk@flash.net>
To: "Commander John" <crazytvjohn@yahoo.com>; <amps@contesting.com>
Sent: Wednesday, July 23, 2008 11:01 AM
Subject: Re: [Amps] Fwd: Re: Bill Orr comment
>
> I can't speak to todays class of ceramic tubes but in the 70's I built
> a number of 3-1000Z amps. The rule of thunb for a well designed AB amp
> was 2:1, output power vs. dissipation. So, yes I agree with the Orr's
> "rule of thumb" here. The 3-1000Z typically did 2:1 RF out 80m-15m but it
> did require a well thought out RF deck. I will not name names here but I
> saw a dozens of what I call stressed 4-1000A amps that made it to the
> 2.5:1 ouput ratio.
>
> It is probably related to the manufacturers design but I have never
> seen 3KW from an 8877 or even 1600W from a 3CX800... Either something is
> being lost in translation or it kinda makes you wonder about the claims
> surrounding our modern ceramic tubes...
>
> 73's Mike K9MK/5
>
>
>
>
> -------------- Original message from Commander John
> <crazytvjohn@yahoo.com>: --------------
>
>
>>
>> Commander John wrote: Date: Wed, 23 Jul 2008 10:23:38
>> -0700 (PDT)
>> From: Commander John
>> Subject: Re: [Amps] Bill Orr comment
>> To: Peter Voelpel
>>
>> Who is this "quack" guru?
>> john w9zy
>>
>>
>> ~~~~~~~~~~~~~~~~~~~~w9zy
>>
>> 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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>>
>>
>>
>> W9ZY
>> .... Commander John ....
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>> W9ZY
>> .... Commander John ....
>>
>>
>>
>>
>>
>>
>>
>>
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