[Amps] 4CX1000A for SSB??

[Mark Marsden]

Hi Randall

Have a look at http://granta.digital-crocus.com/Linear_Design_notes/Spectral_regrowth.jpg

That's a screenshot of the transmit spectrum of my 4CX1000A linear, (Va 2750V, Vs 350V, ZSAC 250mA). It was made by speaking into the microphone normally for a minute and accumulating the trace with the spectrum analyser on peak hold. The lower trace is a barefoot FT1000MP, the upper trace is the output of the linear. 

73, Mark, G4AXX


>>> "ad5gb" <ad5gb at myway.com> 18/03/05 20:33:36 >>>

I just found a chart that listed the distortion characteristics of varioius 
tubes.  I was really disappointed to see how poorly the 4CX1000A ranked amongst
the competitors.  IIRC, I think it was the absolute worst in the bunch.  

I got a couple of these things (with sockets) very cheaply a little while ago
(well maybe longer than that ) and hoped to build something nice for HF out of
them.  I planned to try a grid-driven AB1 configuration at max anode potential
with the best screen/bias regulation I could come up with but based on that 
chart.... it doesn't look like the most wonderful of things to try to do.

Anyway to make these run more satisfactorially?  Cathode drive /w NFB?  Grounded
screen (float the cathode below ground) Anyone with any experience and 
distortion figures better than in that Eimac chart I found?

Thanks


--
Randall D. DuCharme (Radio AD5GB)