>
>On 27 Nov 00, at 8:08, Bob Marston wrote:
>
>< snip >
>
>> The 4CX-1600B with the exception of the Austrailian Emtron design has not
>> seen it's way into commercial designs because Svetlana can not provide a
>> reliable deliver schedule for the tube.
>
>Ten-Tec and QRO now offer amps based on the 4cx1600b.
>Svetlana has, indeed, had difficulty with delivery. Maybe that's
>fixed now. I don't know.
>
>> George Daughters has built a
>> homebrew amp around this tube and his intial reports were good. He hasn't
>> said anything about how the amp has held up in ongoing service.
>
>Here's an update. The "Sunnyvale/St. Petersburg Kilowatt +" is
>still going strong. It's been very reliable. I tend NOT to run it with
>all controls fully clockwise. I probably average about 1300W out,
>and it doesn't get more than warm. I like cooooool components.
>
>I've fiddled a bit with electronic bias switching to minimize heat
>generation during zero signal conditions. I don't use it, because
>I've gotten comments like "It sounds like you're using heavy digital
>processing on your audio" and "You're not splattering, but your
>voice sounds unnatural." My decision not to use it is just an
>individual preference, not a condemnation of the technique. .......
I have never heard an amplifier that had an RF actuated ECBS which
sounded other than the feculence you described, George. The problem with
RF actuation is that during Tx, the bias rapidly switches in and out of
non-linear operation. A better solution is to forget about crowing
roosters, use VOX, and an ECBS that can not switch to non-linear bias
during TX. . With VOX , the amp is in cutoff within approx a
half-second of when the talking or crowing stops. However, if one does
not have Quiet high-speed switching installed the amp., VOX is indeed
painful.
>
cheers, George
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