On 5/21/2011 8:51 PM, Paul Decker wrote:
>
> Thanks for the input, it's really helpful.
>
>
>
> 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.
>
>
>
> 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)
>
>
> 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.
>
>
>
> Am I being paranoid here, should I just go with the full PS rather than
> putting in the buck transformer?
>
>
>
>
>
> Paul
>
>
>
> ------------------------------
>
> Date: Sat, 21 May 2011 08:26:58 EDT
> From: TexasRF@aol.com
> Subject: Re: [Amps] 3cx400A7 and 8877
> To: kg7hf@comcast.net, amps@contesting.com
> Message-ID:<5c583.2effd26f.3b090992@aol.com>
> Content-Type: text/plain; charset="US-ASCII"
>
>
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