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Re: [Amps] 8877 operation at 2KV anode voltage?

To: 'AMPS' <amps@contesting.com>
Subject: Re: [Amps] 8877 operation at 2KV anode voltage?
From: "Dr. David Kirkby" <david.kirkby@onetel.net>
Date: Fri, 03 Aug 2012 03:37:26 +0100
List-post: <amps@contesting.com">mailto:amps@contesting.com>
On 03/08/2012 02:28, Jim Barber wrote:
> Rick's question about refitting an Alpha 76/78 with a GS-35B got me
> thinking again about
> about using an 8877 instead. I have several good tubes that have been
> sitting around for
> years, and now that I'm trying to wean myself away from PA77's they have
> no preordained
> future use.
>
> I haven't used the 8877 below 3500V myself, so I dug around and found a
> Penta Labs data sheet that
> shows Class B operation with 2KV on the anode, although the example
> given is for FM BC.
> Anyway,  pushing the tube up to maximum plate current (1A) results in
> 60ma of grid current, which they
> don't seem concerned about. Output is 1330 watts, at 66.5% efficiency
> when driven with 64 watts.
>
> So... Since the cooling requirements of the 8877 are relatively modest,
> if one found a place for the
> heater transformer it looks like it could be done. Any reason why not?
>
> Thanks,
> Jim N7CXI

I suspect IMD would be poorer at low anode voltages.
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