[ARC5] Why "Noodling" About Sweep Tubes

[wa5jci at flash.net]

I have a HB 4-1000A 6 meter amp with a viewing glass, with shielding 
screen, in the front of the amp tube. It's a beautiful sight. If I 
was to build another amp, which is doubtful, I'd use the glass out of 
a defunct microwave for the glass front because it has a built-in shield. KISS!

de Pete  WA5JCI




At 01:05 PM 10/23/2013, Kenneth G. Gordon wrote:
>On 22 Oct 2013 at 18:24, Fuqua, Bill L wrote:
>
> >   One other thing, when using these tubes you are allowed to let the
> >   plate glow.
>
>Well, yes, but in some cases, like with many of the Eimac tubes, plate "glow"
>is REQUIRED in order to promote "gettering". Those tubes with thin,
>tantalum plates are especially designed for that express purpose.
>
> > Looks great in an amplifier.
>
>I heartily agree! :-)
>
> >    If you use a 4-125A
>
>which is also the same tube as the 4D21 and 6155.
>
> > you can later on upgrade to 4-250A, 4-400A or
> >    3-500z
>
>All of which are required to show considerable color on the plate...again to
>promote and preserve "gettering".
>
> > (if G-G amp) by
> > using larger filament transformer and higher current power supply.
>
>Yes.
>
> > You
> > may have to change the input and output ckts depending on design.
>
>Due to the differences in plate impedances caused by the differences in
>voltage and current.
>
> > If
> > you use continuously variable designs using roller inductors and they
> > are conservatively rated no change needed . Sockets are all the same.
>
>Yup.
>
>However, for what Dave wants to do, I think triode-connected 6146 family
>tubes would be quite good enough...or even 807s or 1625s or 5933s. They
>are all about the same tube anyway.
>
>Ken W7EKB
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