[Amps] 4CX1500B's -- worth using?

David Kirkby david.kirkby at onetel.net
Wed Jun 20 12:52:50 PDT 2012


On 20 June 2012 20:37, David C. Hallam <dhallam at knology.net> wrote:
> That's what I was trying to imply.  The writer of the original post on the
> matter seemed to have the idea that a 4CX1500B was not as good as a
> 4CX1000A.
>
> David
> KW4DH

I don't think they are direct replacements. IIRC the screen voltage is
different, though perhaps not so drastically so that your could not
use the same screen voltage. The filament of the 4CX1500B needs more
current than that of the 4CX1000A if I recall correctly.  The 4CX1500B
will produce a cleaner signal.

I built a twin 4CX1000A amp for 2m, and never did get it working very
well. I recall speaking to John G4FRX (now GW4FRX) and he said the
4CX1000A caused more problems for hams than any other tube. I don't
think its considered one of Eimacs best tubes. The 4CX1500B is
certainly superior.

As I say, there are date sheets on my web site.

dave


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