[AMPS] CW amplifier progress (well, daydream progress) -- lon g

[Rich Measures]

>
>Especially if you're only looking for 1500watts of CW, why not 4CX250B's? 4
>of them, 2kV at an amp or so, and you're there. You should be able to pick
>them up reasonably cheaply with sockets. Over here, I'd reckon to get
>sockets and 4 tubes for under $150. You could probably get away with 3 of
>them if you pushed the HV to 2500v. According to my book, they are rated at
>1500v in plate modulated service, which gives a peak plate voltage (crest of
>modulation, crest of RF waveform of around 4500 to 5000 volts, 

€  indeed, or even a few hundreds of volts more. 

> so pushing them to 2400 or 2500volts in CW should be OK. 

€  providing one does not send A-0/NĜN

>And if you really are CW only,
>you don't need anything too fancy by way of screen grid supply.
>
>Do you really need instant on?
>
€  No one needs instant on if they put an IR motion detector in the radio 
room which switches on the cathode-heaters at the first sign of life. 

>The big advantage of 3-500Zs to my mind is that the blower requirements are
>such that it's likely to be reasonably quiet.
>
€   provided that one copies the split-chassis cooling method used in the 
SB-220.  Air system sockets require a noisy centrifugal blower.    
>
-  later, Peter


Rich...

R. L. Measures, 805-386-3734, AG6K, www.vcnet.com/measures  


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