When were Globe tubes discontinued

ketron281989 · **Posted:** Apr Mon 23, 2012 8:26 pm

Hi guys, I have a RCA model 331 DUO, there are ST type tubes in it now, which came out after the globe style. Could anybody tell me if globe tubes were used up to the mid thirties or were they already phased out by then.

Also if I have a radio that takes 8 pin ST tubes and the rectifier tube is the 4 pin type, would it be period correct, in 1933, to have a globe type rectifier (Since they were 4 pin not 8 pin) and St type for the others in the set.

Thanks

Jon

35Z5 · **Posted:** Apr Mon 23, 2012 8:37 pm

The first 8 pin octal tubes were the metal types introduced in 1935... By that time any set using big pin tubes(or a mix of) would have ST types...

Tom

Scott · **Posted:** Apr Mon 23, 2012 9:31 pm

I am pretty sure that by 1932 globe tubes were gone.

Burnt Fingers · **Posted:** Apr Mon 23, 2012 9:43 pm

+1 for 32 and the 42 is a good contender.

Carl

ketron281989 · **Posted:** Apr Mon 23, 2012 10:59 pm

What do you mean by the 42 being a good contender?

Burnt Fingers · **Posted:** Apr Tue 24, 2012 2:32 am

That a globe 42 was introduced in 32.

Industrial tubes kept the shape a lot longer such as the 866 & 866A.

Carl

Dave Doughty · **Posted:** Apr Tue 24, 2012 2:45 am

If globe tubes were gone by '32, how then could a 42 have been introduced as a globe in '32?

Dave

jkoebel · **Posted:** Apr Tue 24, 2012 4:33 am

Funny, the tube photo @ RMOrg of a 42 is of a globe. http://www.radiomuseum.org/tubes/tube_42.html

35Z5 · **Posted:** Apr Tue 24, 2012 4:57 am

What seems to be forgotten is a year is 12 months long and IF the 42 was introduced in Feb but globe bulbs were not phasing out till May, there would be some globe 42 production...

Tom

Alan Douglas · **Posted:** Apr Tue 24, 2012 7:25 pm

The changeover from S to ST took a while, several years for some types.

David Roper · **Posted:** Apr Tue 24, 2012 8:12 pm

Types such as 50 and 81 come to mind first.

codefox · **Joined:** Nov Sat 27, 2010 6:15 pm **Posts:** 3601

There is no physical reason that I know of why a globe shaped tube could be produced today. Bits and pieces of folks fooling around and making tubes of all sorts have been seen many times. Don't have enough time left to try this.

ketron281989 · **Posted:** Apr Tue 24, 2012 9:14 pm

Wow, thanks for all the replies. Most of my sets are from the 20's and 30's so this information is very valuable to me, Thanks.

My last question: Could I use a globe type tube when all others are ST type?

Burnt Fingers · **Posted:** Apr Wed 25, 2012 2:58 am

Tube shapes are interchangable where they physically fit.

You could have a 280, 380, 80 in globe, ST, GT, and baseless and its all the same tube for instance. For the nitpickers on here the later 80's were 5Y3's with a 4 pin base :roll:

Carl

ketron281989 · **Posted:** Apr Thu 26, 2012 4:53 am

Thanks Carl

When were Globe tubes discontinued

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