RadioBanter - View Single Post

May 9th 06, 01:19 AM posted to rec.radio.amateur.homebrew

See down a bit....

On Mon, 8 May 2006, wrote:

On Mon, 8 May 2006 15:39:18 -0400, Straydog wrote:

FYI,

The tubes designed to work on 12 v for the plate might be best, but there
are a number of battery filament tubes that also migh give you some
results. eg. 1L4,1T4,1U4,1R4,1R5, etc (all 7 pin miniatures). (there was a
series of 8 pin octal tubes, too). Most of them ran filament voltages of
1.4 volts at 50 ma current. I built a audio oscilator with a 1T4 (pentode)
as a kid and it would oscilate down to 7 volts on the plate!! Most of those
tubes were designed for up to 90 v on the plate. Power audio tubes were like
3S4, 3Q4, 3A4, etc (which would run 3.0 v at 50 ma, or center taped filament
at 1.4 v and 100 ma). The 3A4, pentode, as RF amplifier was good for
something like 1/2 watt output or so, not bad for QRP and no transistors.

Yep used them and the 3s4 is very happy with 18V (two 9v batteries)
and makes a near optimum regen at 27V (three 9v batteries).

I'd already mentioned the 1ad4 and 5678 these are hearing aid tubes
that are very small with 1.4V 50ma filaments. They work very well
with 22.5V so 18 to 27 V is both easy and work well for them.

Common tubes like the 6ba6, and many of the other AA5 (6be6, 6ba6,
6av6 and they 12V versions) all work well at far less than 100V and
save for the audio ouput tube (50C5) ran fine at 18V.

For an oddball there is the 8058 a 12V nuvister that made a fine
VHF osc, amp or mixer.

There was an older series of battery fillament tubes, designed for lead
acid cells (all were 2.0 v on filaments and not much amperage, either).
You'll have to consult an older tube manual for those if you want to try
them.

Your thinking of #30, 31, 32 and 45.

Nah, don't have to go back that far. I got a RCA tube manual copyright
1960, and it shows, for example, 1D5-GP, 1G5-GT, 1D7-G, 1E7-GT, 1F4,
1F5-G, 1F6 as all 2.0 volt filament tubes, and most of them are octal
bases, and one or two are 5 or 6 pin non-octals. And, I also know there
were a couple numbers not made by RCA, but I spend most of my time with my
nose in the RCA manual.

And, I'm having a lot of fun in my early retirement years building a whole
(retro) tube station from partly the junkbox, partly surplus, partly new,
partly Radio Shack parts. But, I didn't know too much about the 12 v plate
tubes although I knew they existed. So, after this year's recent posts, I
started looking up the 12??blah-blah numbers in that tube manual and there
is a lot there. Now gotta decide if I want to go that route or stay with
the 1L4, 1R5, 1U4, 1T4, etc., route or use 6.3 v fil-cathode tubes with
100-200 v on plate. Part of me likes the idea of octal tube bases because
they are so much easier to put into and take out of sockets (because of
the keyed pin). Couple times in my life I dinged up pins on miniature
tubes because I didn't look carefully at the pins on the tubes and the
holes on the socket to line them up. Seems neater to have the keyed post;
just aim the center of the post for the big hole, and then spin it around
till it pops in. :-)

1.4 v filament tubes wouldn't throw a lot of heat in the summer time,
either. If I built both kinds of rigs/receivers, I guess I could use the
"hot" rig in the winter as extra heat for the room. And, the "cool" rig in
the summer. ;-)

Thanks for your comments, otherwise.

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On Sun, 7 May 2006, wrote:

Anybody know any tubes...st or gt shape preferred that will work on 12
volts plate voltage for small 1 tube regens...possibly a stage or two
of amplification also.

I know there were automobile radio tubes made that didnt need vibrators
but dont know any numbers myself.