[Amps] 3cx400A7 and 8877

[Roger (sub1)]

On 5/21/2011 8:51 PM, Paul Decker wrote:
>
> Thanks for the input, it's really helpful.
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> With respect to the 8874.  At first I was under the impression that the 8874 and the 3cx800a7 were interchangeable except for the heater voltage, the 8874 being 6.3 and the 3cx800 being 13.5.   When I checked the data sheet to make sure I noticed the absolute max voltage of the eimac 8874 listed as 2200 VDC with a working voltage of 2000, while the absolute max on the 3cx800 is listed as 3500 with a working voltage of 2250.
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> So...they don't seem to be completely drop in replacements of each other, at least going from the "big one" to the little one, but man they sure look the same on the outside!

Ahhh..You sure you have the right tubes?  I have both right here and the 
3CX800 is twice the size of the 8874.  Even then the 3CX800 isn't very 
big.  http://www.rogerhalstead.com/ham_files/Amp_files/Tube_photos.htm  
Front row, top photo  8874 on the left, 3CX800 on the right.  BTW that 
8295A which is larger than any of the others in the back row, only has a 
1000 watts plate dissipation while the next two (Chinese FU728F) and the 
4CX1500B  are 1200 and 1500 watts plate dissipation respectively.

73

Roger (K8RI)
>
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> I was talking with another ham today who is also tube knowledgeable and he thought the same as I, that they were completely interchangeable save the heater. 
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> Am I being paranoid here, should I just go with the full PS rather than putting in the buck transformer?
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> Paul
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> ------------------------------
>
> Date: Sat, 21 May 2011 08:26:58 EDT
> From: TexasRF at aol.com
> Subject: Re: [Amps] 3cx400A7 and 8877
> To: kg7hf at comcast.net, amps at contesting.com
> Message-ID:<5c583.2effd26f.3b090992 at aol.com>
> Content-Type: text/plain; charset="US-ASCII"
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