TOTALLY OT QUESTION (Vacuum Tubes)

weirdjim

weirdjim

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weirdjim
... except that some of the 1920s aircraft used them sparingly ..

Been looking for a week and can't find pinout or filament voltage of a #427 DeForest Audion vacuum tube. 5 pin, no plate cap. Any suggestions (my oldest ARRL 1961 and 1939 Aeronautical Radio manuals don't list them)?

Jim
 
weirdjim said:
... except that some of the 1920s aircraft used them sparingly ..

Been looking for a week and can't find pinout or filament voltage of a #427 DeForest Audion vacuum tube. 5 pin, no plate cap. Any suggestions (my oldest ARRL 1961 and 1939 Aeronautical Radio manuals don't list them)?

Jim
Click to expand...

So, the equivalence guide shows the RCA 227 as being equivalent to the DeForest 427. http://www.vacuumtubesinc.com/TubeTidbits/AntiqueTubeEquivalents.aspx

And the RCA guide shows the 227 thusly: http://www.nmr.mgh.harvard.edu/~reese/RC10/RC10-33.GIF

Take the suggestion for what it's worth - this is the internet....
 
I'm impressed by how quickly the OP got an answer to an obscure technical question.
 
Do you have the equipment that it is used in? Analyzing the socket connections might get you there. There is a tube of that type for sale on ebay. No bids, listed a $7
 
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C'mon Jim, it isn't that hard. Below is one with even the voltages/current that are typical marked on it apparently..

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Silvaire said:
...as did the AIM7 air to air guided missile. :yes:
Click to expand...

...and some older FAA radar installations until about five years ago, and some transponders still in use, and guitar amps still being manufactured...

I always thought the tube radars had a warmer, more analog look to them. ;)
 
PW_Plack said:
...and some older FAA radar installations until about five years ago, and some transponders still in use, and guitar amps still being manufactured...

I always thought the tube radars had a warmer, more analog look to them. ;)
Click to expand...

LOL.

Because, like, they are warmer and analog? :D
 
Boy, does this bring me back. When I was a kid, my Dad had a TV repair shop. My first job was Sat mornings, pulling tubes out of old TV chassis and amps and testing them with an RCA tube tester. When I graduated to the repair bench, the first dianostic step was to plug in the set, turn it on and start tapping tubes with the butt of a screwdriver.

Still like the sound of a good old tube type audio system.
 
These are simple vacuum tubes that you can figure out the pin out by just looking at the tube itself. Start with the filament pins. On an Ohmeter these will show as a few ohms. The cathode grid and plate are constructed coaxially. The cathode being the inner one surrounding the filament, followed by the grid and the plate or anode surrounding the whole assembly. In the early days most tube filament operated on 6 volt batteries. With plate voltages ranging from 100 to 250 VDC. Higher voltages were used on transmitting tubes (RF amplifier).

As a note: The invention of the vacuum tube curtailed the development of semiconductor valves (transistors) that was also under experimentation at the time. The vacuum tube became so sucessfull and popular that experimentation on semiconductor materials was stop. The carbon microphone is an example of semiconductor material being tested at the time.

José
 
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Tubes can still be had, new. Made in Russia for the most part. When I find my old Heathkit SB-100 I'm going to get some new tubes (6146A for the finals) and put that sucker back on the air. "Real radios glow in the dark" :D
 
Ghery said:
Tubes can still be had, new. Made in Russia for the most part. When I find my old Heathkit SB-100 I'm going to get some new tubes (6146A for the finals) and put that sucker back on the air. "Real radios glow in the dark" :D
Click to expand...

Heh. My first rug was an HW-101 someone else built, and job #1 on it was swapping new 6146B tubes in and neutralizing them. A solid 100W out and kept the cold spare bedroom where the radios lived, warm in winter.
 
Chip Sylverne said:
Boy, does this bring me back. When I was a kid, my Dad had a TV repair shop. My first job was Sat mornings, pulling tubes out of old TV chassis and amps and testing them with an RCA tube tester. When I graduated to the repair bench, the first dianostic step was to plug in the set, turn it on and start tapping tubes with the butt of a screwdriver.

Still like the sound of a good old tube type audio system.
Click to expand...
Don't leave out "And looking for a purple glow". :yes:
 
I've seen wire wrapped connections used in ring laser gyros. It is what it is!
 
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