Over the years I’ve collected random tubes. I have 2 that have no identifier other than manufacture and date code,
This Raytheon looks to be a dual triode with an octal base.
This Westinghouse may be a pentode, or not, I have no idea
Any help is appreciated.
Tube identification help please
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Tube identification help please
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Stevem
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Re: Tube identification help please
The first tube looks like a full wave rectifier, the second looks like an output tube.
Ohm out each tube to find out which pins are the heater as those two pins( if the heater is not open ) are the only two that should read a resistance although in the tube that’s not a rectifier there may be two pins that are a dead short to each other by design.
The second tube, the one that looks to be an output tube might be a 50L6GT since it looks to have all 8 pins.
A resistance check on the heater would read much much higher then a 6v6 or a 6K6 for example.
A duel triode type could have a common cathode and internally you would only see 7 wires going to 7 pins, and the 8th pin if it has one will not have a internal connection.
But if you do not have a tube tester with selection knobs I don’t really know how you would safely find out what these two tubes are unless someone else here has any ideas.
Ohm out each tube to find out which pins are the heater as those two pins( if the heater is not open ) are the only two that should read a resistance although in the tube that’s not a rectifier there may be two pins that are a dead short to each other by design.
The second tube, the one that looks to be an output tube might be a 50L6GT since it looks to have all 8 pins.
A resistance check on the heater would read much much higher then a 6v6 or a 6K6 for example.
A duel triode type could have a common cathode and internally you would only see 7 wires going to 7 pins, and the 8th pin if it has one will not have a internal connection.
But if you do not have a tube tester with selection knobs I don’t really know how you would safely find out what these two tubes are unless someone else here has any ideas.
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Re: Tube identification help please
Great suggestion…
The Westinghouse has 4 ohms between pins 1 and 4.
The Raytheon has 4 ohms between pins 7 and 8.
These tubes are most likely worthless for guitar amps. I just hate to throw anything out that might be useful.
The Westinghouse has 4 ohms between pins 1 and 4.
The Raytheon has 4 ohms between pins 7 and 8.
These tubes are most likely worthless for guitar amps. I just hate to throw anything out that might be useful.
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Stevem
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Re: Tube identification help please
From what I can tell from my RCA tube book the tubes who’s heater looks to be 1 and 4 would not be a guitar amp tube.
The one with 7 and 8 could be a 6sl7 or a 6sn7
The one with 7 and 8 could be a 6sl7 or a 6sn7
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
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martin manning
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Re: Tube identification help please
Put them in the freezer for a bit and then see if anything shows up with the condensation when you take them out. I've had some luck doing that, but not always.
Re: Tube identification help please
I could use a 6SC7, which also has heaters on 7-8, I have a 5B4 Super on my bench now. I could compare a NOS to the existing tubes, which seem good, but I’d like to compare gain and noise levels.
Re: Tube identification help please
Interesting…they’re in the freezer now.martin manning wrote: ↑Mon Sep 21, 2026 10:34 pm Put them in the freezer for a bit and then see if anything shows up with the condensation when you take them out. I've had some luck doing that, but not always.
Re: Tube identification help please
The freezer trick didn’t work. No biggie.Bob-I wrote: ↑Tue Sep 22, 2026 1:19 amInteresting…they’re in the freezer now.martin manning wrote: ↑Mon Sep 21, 2026 10:34 pm Put them in the freezer for a bit and then see if anything shows up with the condensation when you take them out. I've had some luck doing that, but not always.