[ARC5] Why "Noodling" About Sweep Tubes

[Dennis Monticelli]

I just remembered another tube.  The 829B was very expensive in the WW2 era
but it's practically free at the hamfests now.  You find them mil grade
NIB.  I don't think I paid more than $2 for mine.  You can parallel the two
tetrode sections or use them push-pull.  I think they're good for 40W plate
per section.  12V heaters and a 7 pin socket (Septar?) that is worth more
than the tube.

Dennis AE6C


On Wed, Oct 23, 2013 at 4:37 PM, Ian Wilson <ianmwilson73 at gmail.com> wrote:

> "Although they are 'beam tubes' their advantage over other types of beam
> tubes is that their beam-forming plates are connected to separate pins, and
> not to the cathode, as all octal-based beam-tubes are."
>
> Not sure about this: the 4-125A is a tetrode, and the 4E27 can manage
> suppressor grid modulation, which would seem to suggest more of a
> traditional g3?
>
> 73, ian K3IMW
>
>
> On Tue, Oct 22, 2013 at 2:13 PM, Kenneth G. Gordon
> <kgordon2006 at frontier.com> wrote:
> > Bill is certainly right about the 4E27 and the 4-125 and its pulse
> variants. I
> > had forgotten about those. Either would be perfect for your uses, and
> both
> > are cheap on eBay, especially the pulse variants which are not as easily
> > recognized.
> >
> > There was a later variant of the 4E27: the 5-125B/4E27A. Those often show
> > up too, but sell for higher prices.
> >
> > The PD of the 4E27 is 75 watts, while that of the 4E27A is 125 watts.
> >
> >
> > Either one uses an 813 socket.
> >
> > Although they are "beam tubes" their advantage over other types of beam
> > tubes is that their beam-forming plates are connected to separate pins,
> and
> > not to the cathode, as all octal-based beam-tubes are.
> >
> > Ken W7EKB
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