"Ross Matheson" schreef in bericht
...
OK, we've all seen those cutaway tube illustrations, and maybe even taken
sharp cutters to a dead tube's plate structure after breaking the glass.
This little tube has the most open plate structure I've ever seen. Data at
http://www.mif.pg.gda.pl/homepages/f...25/s/S6F33.pdf
It's a special quality dual control HF pentode. The plate structure,
looking
down from the top, would be in the shape of a U - except the curved part
is
only a thin band joining the two straight sections, at one side. From the
other side you can see the whole grid structure between the two plate
ends.
This scan is taken looking into the open end of the "U", from that side.
I don't know where this would have been used - even the data sheet says
"Tentative" - but thought it might be interesting enough for a geeky note.

RdM
nz not zn


I thought I've seen it all with the PL802 and E55L , but this one is extreme
!!
Myabe if you take the shield out of an EF184 ..... It's hard to see the
anode trough it .

Ronald .

"Mikkel C. Simonsen" wrote:

: Ross Matheson wrote:
:
: This little tube has the most open plate structure I've ever seen. Data at
: http://www.mif.pg.gda.pl/homepages/f...25/s/S6F33.pdf
:
: The "rocket brand" 6N1Ps I have are simmilar. The plate consists of two
: "U"s with the bottom ends facing the grid, so the sides are completely
: open.
:
: Does anybody know the reason for these open structures?

Good question! I was wondering why, too. Less capacitance to plate?

: Best regards,
:
: Mikkel C. Simonsen

RdM

Ross Matheson wrote:
OK, we've all seen those cutaway tube illustrations, and maybe even taken
sharp cutters to a dead tube's plate structure after breaking the glass.
This little tube has the most open plate structure I've ever seen. Data at
http://www.mif.pg.gda.pl/homepages/f...25/s/S6F33.pdf
It's a special quality dual control HF pentode. The plate structure, looking
down from the top, would be in the shape of a U - except the curved part is
only a thin band joining the two straight sections, at one side. From the
other side you can see the whole grid structure between the two plate ends.
This scan is taken looking into the open end of the "U", from that side.
I don't know where this would have been used - even the data sheet says
"Tentative" - but thought it might be interesting enough for a geeky note.

RdM
nz not zn

That's neat! I've always had a special place in my heart for the 6CB6
because of its open structure (never mind that it's also a useful tube!)
but this one takes the "Visible Tube Award" for sure.

Your second scan was very nice, shows it very well.

For comparison, a 6CB6 is he
http://www.dogstar.dantimax.dk/tubestuf/pinups/6cb6.jpg

Keeping plate-to-everything-else capacitance low would seem to be the
main benefit of having such a low anode area.

Cheers,
Fred
--
+--------------------------------------------+
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| Projects, Vacuum Tubes & other stuff: |
| http://www.dogstar.dantimax.dk |
+--------------------------------------------+

Fred Nachbaur wrote:

: That's neat! I've always had a special place in my heart for the 6CB6
: because of its open structure (never mind that it's also a useful tube!)
: but this one takes the "Visible Tube Award" for sure.
:
: Your second scan was very nice, shows it very well.

Thanks!
Must remember to de-dust (and not smear lettering more often though!
There's a few available if anybody can think of a useful application ...

: For comparison, a 6CB6 is he
: http://www.dogstar.dantimax.dk/tubestuf/pinups/6cb6.jpg

Wow, very similiar plate structure, indeed. Can't see any wires on those
intermediary pins though, wonder what they are doing? Just supports?

: Keeping plate-to-everything-else capacitance low would seem to be the
: main benefit of having such a low anode area.

It's the only logical conclusion I can come to, indeed, and it fits their
intended HF applications (6CB6 included).

: Cheers,
: Fred

And a fine morning to you up there in Summer:-)

Still amazing .......
Most of the time "S" is much higher with such open constructions .....

"Ross Matheson" schreef in bericht
...
Didn't do it justice at 150dpi, lowest quality jpg.
Here's a rescan, opposite side, 600dpi, slightly higher quality, only 30k.
Brand new tube, had a slightly mottled film on the glass. Unfortunately,
trying to clean it smeared some of the lettering. Oh well, price of
detail.
Note the bottom grid spiral is slightly squashed, too :-)
Much larger and clearer picture. Posted again at abpr :-)
RdM

"Mikkel C. Simonsen" wrote in message
...
The "rocket brand" 6N1Ps I have are simmilar. The plate consists of two
"U"s with the bottom ends facing the grid, so the sides are completely
open.

Ah, like a 12B4 or 6AS7/6080? Only those are square bent, not U.

Tim

--
In the immortal words of Ned Flanders: "No foot longs!"
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