[Amps] Chinese 4CX1000A from Alpha

[Roger (K8RI)]

On 11/15/2013 7:27 PM, Vic K2VCO wrote:
> According to the data sheets, they are very different. The 1500B has a
> special grid structure that produces a very low level of IMD, if you
> operate them according to the parameters on the data sheet -- which
> includes a screen voltage of 225 instead of the 325 spec'd for the
> 1000A.

Doesn't the Alpha run the lower screen voltage?
If it does there shouldn't be a problem.
In past amps, I've used the interchangeably although I never measured 
IM, I never had a bad report.  OTOH that was quite a while ago.

73

Roger (K8RI)

The efficiency is low compared to the 1000A as it is spec'd.
> Maximum output from the 1500B at 3kV is less than 1500w per tube, even
> with the greater plate dissipation.
>
> When I started my amp project I had some 1500B pulls that I thought
> about using, but since I wanted to use a single tube, and since I work
> almost entirely CW, I figured the 1000A was more appropriate.
<snip>