>
>Rich Measures wrote:
>
>>>and last ,i'm looking for a high power amp
>>>for 2 meter ssb ( 500 + out put) any body
>>>want to sell one?
>>
>>A pair of 4cx250Rs in parallel, self-contained, designed and built by
>>yours truly. 20db gain. Class AB1. About 1000pep watts out on SSB.
>>designed for10w pep drive. The built in 2200v power supply is not
>>suitable for FM, RTTY or A0. $100 plus ups. 120v/20a. Must be tuned up
>>with a keyer sending 50wpm dits, or with a tuning pulser.
>
>The gain is right - and by goodness the price is certainly right -
>but expect no more than 500W PEP of *linear* SSB. Otherwise expect to
>lose a lot of friends.
>
? The 7580/4CX250Rs have 400v on the screens. According to Eimac's
curves, c.1.3 peak amperes of anode current flows when the grid potential
is 0V and the screen potential is 400V. The 1.3a constant-current curve
appears to be reasonably linear up to 0V on the grid. By my calculation,
the pep input is around 1850w.
>No criticism of Rich's particular design; the limitation is in the tubes
>themselves.
>
? Did you perhaps presume that the 7580 has the same power capability as
a 4CX250B?
>
- later, Ian
Rich...
R. L. Measures, 805-386-3734, AG6K, www.vcnet.com/measures
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