> That Swan amplifier is a good example of an amp that needs an
> "electronic vox biasing" kit installed in it to cut down on that
> awfully high idling plate current. They're available from Ameritron
> all fully assembled and ready to drop in.
> 73 from Fern
>
>
>
> ----- Original Message -----
> From: "Gary Smith" <wa6fgi@sbcglobal.net>
> To: <w2cqm@juno.com>; <amps@contesting.com>; "Scott Townley"
> <nx7u@arrl.net>
> Sent: Sunday, July 09, 2006 11:01 PM
> Subject: Re: [Amps] Question about glowing 3-400z's
>
>
>> The higher the frequency, the more the color changes from a red glow
>> towards
>> white. (From 80/75m to 10m)
>> 73,
>> Gary...wa6fgi
>>
>> ----- Original Message -----
>> From: "Scott Townley" <nx7u@arrl.net>
>> To: <w2cqm@juno.com>; <amps@contesting.com>
>> Sent: Sunday, July 09, 2006 8:44 PM
>> Subject: Re: [Amps] Question about glowing 3-400z's
>>
>>
>>>I would say that, considering the idle plate dissipation is
>>>260W/tube, that
>>> some color would be expected.
>>>
>>>
>>> At 19:25 2006-07-09, w2cqm@juno.com wrote:
>>>>I'm working for the first time on a pair of 3-400Z's in a Swan Mark
>>>>I. On
>>>>both the high and low power position, the amp is making exactly
>>>>the
>>>>instruction manual's specified idle current. Plate voltage is
>>>>2900VDC and
>>>>idle current is 180ma. With key down and no excitation at this
>>>>level, the tubes begin to glow to a color that I consider to be
>>>>a
>>>>bright red. The plate current meter shows no rise in current draw
>>>>during
>>>>this entire process. The amplifier loads perfectly and when
>>>>driven with
>>>>100w , power output is about 1100W. The question is whether this
>>>>"glowing" is the normal characteristic of a pair of Eimac tubes??
>>>>Any
>>>>comments will be appreciated. Ron W2CQM/3
>>>>
>>>>
>>>>
>>>>________________________________________________________________________
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>>>
>>>
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>>
>>
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>
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