So I was given a really cool vacuum tube portable
AM radio. I'll post a few things about it and add
some more info as I can.
It is made by CBS Columbia. I know nothing about
them. The style of the case makes one think that
this unit is transistorised. However, inside there is
space for an old A battery and also a B battery.
There are 4 vacuum tubes. A 1R5, 1U4, 1U5, and
a 3V4.
The radio has an AC line cord and works well, except
that there is probably more AC hum than there should be.
I guess it needs to be recapped.
It has a speaker with a huge magnet and the audio is very loud.
It is very selective. I am in Hartford and I can hear CHML 900
IN Hamilton, Ontario right below our local 910 station 4 miles
away. The model number is 5220, and I had a picture of another
one (different color but otherwise the same) on the internet a short
time back. This radio was built to last. I don't know where it has
been in the last fifty or so years, but it is in very good condition.
I really like it a lot.
More to report soon.
Best wishes to all
Brooce, Part 15, Hartford Ct
Battery powered tube radios were popular in the mid to late '50s so I would guess yours is of that vintage. My brother had one and it was a nice radio but it was hard on batteries. His used a D cell for the "A" battery and a 90 volt pile battery for the "B" supply. The 90 volt battery was easy to get but it was expensive and it didn't last long. At the time I had a vendor's licence and could get them for him wholesale at about half the retail price. Otherwise, he probably couldn't afford to use the radio.
A few years ago he told me he had trashed the radio but had saved the tubes for me. He gave me the tubes, probably the same types that you mentioned but it is disappointing that he no longer had the radio.
Neil
If you Google the name and model
number you will find several service
manuals for this unit -- one is from
1954. It seems that this unit was made
from 1953 until 1960. There are Conelrad
(sp?) markings at 640 and 1240 kHz.
The tubes warm up very fast. It only takes
a second or so.
My unit is light brown in color. The one
on E-Bay is green. The guy only wants $5 for the radio
and a couple of dollars for shipping.
I would snap it up, but I have too many things here already.
I hope somebody gets it so it won't
go into the trash.
When I was 5 years old or so in 1959
or 1960 I was down the street playing
with some other kids. I ran through
the kitchen of that house and heard
a radio playing on the counter in the
kitchen. The sound was very distorted.
I asked the mother there why the radio
sounded like that. She told me it was
a battery radio and the the batteries
were running low. I suppose it might
have been a vacuum tube portable.
Brooce
It's unfortunate your brother tossed that radio.
I have parted with so much radio gear - one
way or the other - - and have regretted much of it.
Then there was that blasted Heathkit Seneca VHF
boat anchor. I was glad to see that go. That's a
funny story.
Anyhow, sometimes there are choices that
have to be made - because there is no place to
stow a lot of this stuff.
I think this particular radio I aquired needs 3 volts
for the filiments. Probably 3 volts for that one
3 volt filament tube - and 3 volts again -
for the 3 one volt filament tubes that are left.
Yeah - that's the 3V4, and then the 1R5, 1U4, and
1U5 - a series filament string. So 2 D batteries would
run the filaments for a little while. Then there's that
90 volt plate issue. Everybody is telling me to get
ten 9 volt batteries and put them in series. I will
probably do that someday. Maybe. One would have
to be very careful with that. That's a ldt of energy
and voltage that could do damage.
This is wonderful gear and the experience of using
it is very fulfilling. I'm glad you feel that way too,
as well as so many of the other people in our Part 15
group - over here - and at the ALPB site.
Thanks for the great radio stories.
Best Wishes,
Brooce