The PHILCO Phorum

Yup, Looks like a 42 or a 2A5.
Terry

My first guess would be 42, although there were also some globe 43 tubes with the Philco brand.

"B2" is the date code, where "2" stands for 1932. I have a paper around here somewhere that gives the letter meanings, each letter is for a different month.

In 1936 (I think), Philco switched to a different date code where the first letter stood for the particular quarter of the year.

O - 1st quarter
P - 2nd quarter
U - 3rd quarter
S - 4th quarter

Sylvania date codes are the same, as Philco tubes were made by Sylvania until 1940 when Philco bought controlling interest in National Union.

Need a different view?

Drop it in your tube tester and start at 2.5v on the heater. Crank in up till it looks right. 2.5v is a 2A5 or 95, 6.3v 42 or 25v is a 43.
Terry

Quote:Drop it in your tube tester and start at 2.5v on the heater. Crank in up till it looks right. 2.5v is a 2A5 or 95, 6.3v 42 or 25v is a 43.

Following this procedure, I think that it is a 42. THANKS

You are very welcome. You won't find too many globe toobs after about 1932. The globe style is just a poor design. Not enough support to the elements inside the toob. Kewl to look at but I always consider them first if there is a problem. The 42's I've seen have been good but on the other hand 24's,32's and 34's and seem to be the most problematic.
Happy radio hunting!!
Terry

It might be a type 18 as well.

Dennis

I do have a set on the bench right now with 42s. What's the worst that could happen if it's not a 42?

Well I suppose it's possible but I think there is a lots more 42's than 18's. Any way the 18 has a 14v heater. If it is an 18 it would only light up to half brightness.
Terry

Some early Philco globe jobs had the number up high on the side in a circle.

Maybe look there with an LED flashlight, it can bring out things on occasion.

If you still can't make out the type but it tests A-OK as a 42, give it a go in the radio.

Dennis

The radio works with it....it's a 42.

I think that maybe 1933 may have been the last year for globe/balloon types, my Philco 60L has a balloon 42 in it and it's a 1933 model. I agree about the globe/balloon designs being more trouble prone, especially audio output tubes, more microphonics, more shorted elements. Why the audiophools, who claim high fidelity as the highest calling, would pay a premium for these makes little sense to me. I have noticed that the new production globe/balloon 2A3s and #50s have larger micas insulators at the top so the elements aren't just free standing like the old ones, some even use porcelain insulators.
Regards
Arran

I've got a Philco 42 globe tube with the date code of "H 3". So, using the date code Ron mentioned gives me a date of August, 1933? I was under the impression that the glove Philco 42 was only made in 1932. Maybe I'm mistaken. Can anyone provide any clarity on this? The good news is that this tube is good and tested pretty strong.

Thanks, Tom

I would have to find my date code sheet, and right now I honestly do not know what happened to it. I seem to recall that the letters used between 1930-1935 or 36 when they switched to the OPUS code were not in alphabetical order.

Philco globe tubes were made as late as early 1933, but just how long, I don't know at present. I'm at work and all of my data is at home.

Chuck, do you have anything?