What are the tubes in it? The numbers may be on them still, or on a paper in the cabinet with the tube layout.
You could write the web master of Nostalgia Air. He is very helpful.
Keep in mind too that even though some companies claim to be manufacturers, they actually might be made by RCA or Philco or GE or some other larger company.
Gabe
You could write the web master of Nostalgia Air. He is very helpful.
Keep in mind too that even though some companies claim to be manufacturers, they actually might be made by RCA or Philco or GE or some other larger company.
Gabe
RMS said:
The square cans are I.F. Transformers (coils?) radio is not really my thing. They arent tubes though.
If you add up all the tube voltages, you get 127, which is close enough to run off the line..
are you sure there are two 7B7's ? if there was only one it would equal 120v (dead on), and have 5 tubes = AA5. which was a common design of radio from i guess the 40's until SS took over.
AA5s were originally octal (bigger tubes w/ 8 pins, and a bakelite (?) base. as things progressed (50's i guess..) they used smaller 9 & 7 pin minature tubes. (these have no plastic base, and are generally from 1/2" to 1" around.
Thats about all i know about radios
Hi RMS,
That was a mid 40's design, and probably a shortwave radio, having an RF amplified front end.
During WWII, radio manufacturers did not have much components to choose from. The newest stuff was used by the military. Loctal tubes were designed to keep tubes in their sockets in airplanes. They did become available around 1944-45. But since most of the more popular radio tubes were being used for the war effort, manufacturers had to use what was available. So they combined the two types, octals (the 8 pin ones with the plastic key bottom) and loctals.
The7B7's, 14B6, and 14Q7 (you sure Q?) are loctal design, if memory serves. The 50A5 is the power audio out, and the 35Y4 the rectifier.
I wonder if you could take a digi-pic of it. I may be able to help ID it.
Before Colt45 says nay, the other two coils would be under the chassis. One may also be the flat antenna coil on the back panel, with a switch for local or distance (or inside and outside), which would switch between the flat coil and the coil under the chassis, which would allow for the use of an antenna and ground.
The oscillator coil is a given, making for three under chassis coils, two IF coils, and three gangs of tuning capacitance.
RMS, if you see three lugs on either side of the tuning capacitor, then it is an RF amplified superheterodyne. If you have a band switch (AM-Shortwave), then... it is a SW radio.
Value of a radio at that time, I guess as with all times, depends on collector fancy. At one time the Cathedral was sought after. Then the bakelite. Now it is the plasticon ones. Who knows what it will be in a few years.
Hope this helps some.
Gabe
That was a mid 40's design, and probably a shortwave radio, having an RF amplified front end.
During WWII, radio manufacturers did not have much components to choose from. The newest stuff was used by the military. Loctal tubes were designed to keep tubes in their sockets in airplanes. They did become available around 1944-45. But since most of the more popular radio tubes were being used for the war effort, manufacturers had to use what was available. So they combined the two types, octals (the 8 pin ones with the plastic key bottom) and loctals.
The7B7's, 14B6, and 14Q7 (you sure Q?) are loctal design, if memory serves. The 50A5 is the power audio out, and the 35Y4 the rectifier.
I wonder if you could take a digi-pic of it. I may be able to help ID it.
Before Colt45 says nay, the other two coils would be under the chassis. One may also be the flat antenna coil on the back panel, with a switch for local or distance (or inside and outside), which would switch between the flat coil and the coil under the chassis, which would allow for the use of an antenna and ground.
The oscillator coil is a given, making for three under chassis coils, two IF coils, and three gangs of tuning capacitance.
RMS, if you see three lugs on either side of the tuning capacitor, then it is an RF amplified superheterodyne. If you have a band switch (AM-Shortwave), then... it is a SW radio.
Value of a radio at that time, I guess as with all times, depends on collector fancy. At one time the Cathedral was sought after. Then the bakelite. Now it is the plasticon ones. Who knows what it will be in a few years.
Hope this helps some.
Gabe
Gabe,
I did a Double check and yes there are two 7B7 tubes (6 in total)but the 50A5 was replaced with a 50L6GT the only one that has a bakelite base all the other tubes have aluminum bases.
Yes I do see three lugs, to me they look like mounts with ruber isolation o rings? Is this a RF amplified superheterodyne type that you mentioned? also, can you explain some more about what I.F. transformer do and what I.F. means.
This raidio is in a rectanguliar wood box with a dial that reads from 160 to 55, one light bulb, and two dials. A sticker on the speaker says ROLA.
Thanks for your help!
Rob
I did a Double check and yes there are two 7B7 tubes (6 in total)but the 50A5 was replaced with a 50L6GT the only one that has a bakelite base all the other tubes have aluminum bases.
Yes I do see three lugs, to me they look like mounts with ruber isolation o rings? Is this a RF amplified superheterodyne type that you mentioned? also, can you explain some more about what I.F. transformer do and what I.F. means.
This raidio is in a rectanguliar wood box with a dial that reads from 160 to 55, one light bulb, and two dials. A sticker on the speaker says ROLA.
Thanks for your help!
Rob
Hi RMS,
Sorry for not answering sooner.
IF. Intermediate frequency. I will try to make this short and sweet, but here goes. One needs some history:
In the early days of radio there was the need to make a set with as few parts as possible while making it most sensitive. Things like positive feedback AKA regenerative feedback, reflex (feeding back audio through the same tube as RF, where one tube did double duty), and TRF, or Tuned Radio Frequency, which used two or more stages of manually tuned circuits were used. The latter being the most popular. Hence why radios of the twenties had many knobs. One had to tune two to three controls to the same frequency so each stage amplified the same signal a certain amount. This made the radios very sensitive but cumbersome. A few companies tied the three or four stages together so one could use only one knob. But the other negative was that the whole band was not always received well due to inaccuracies with the tuning. In other words, some parts were more sensitive than others.
In comes the superheterodyne. I think it was aroung 1923, Edwin Armstrong (who also invented FM, BTW) invented the circuit where the incoming signal was mixed with a locally derived signal (the local oscillator inside the radio) and a sum and difference signal was created. If the local oscillator was tuned in sync with the desired incoming signal, then the sum and difference signals were constant. This way one can then send either the sum or difference signal through several additional stages of tuned amplification. The difference signal was chosen. Through the early thirties this difference signal could be anywhere from 120kHz to 500kHz. They finally settled with 455 kHz as the intermediate frequency.
So, if you tune to 900 on your dial, the local oscillator was tuned to 900+455, or 1355kHz. Then the two will mix to make 455kHz, and it can be amplified many times by a TRF like circuit tuned only to 455kHz. That is the Intermediate Frequency or IF. So all stations eventually wind up being 455kHz inside the radio.
In your case, there is additional RF, or Radio Frequency (incoming signal) amplification before going throgh the IF conversion stages. Hence why you will hear the first or second tube in a radio called the mixer or converter.
You have what sounds like it is a nice radio. If you can take a picture of it I may be able to help further. I happen to have one that sounds like the same as yours.
Here is a good site with more details and pictures:
http://home.attbi.com/~radiowarren/hetbasic.html
Hope this helps,
Gabe
Sorry for not answering sooner.
IF. Intermediate frequency. I will try to make this short and sweet, but here goes. One needs some history:
In the early days of radio there was the need to make a set with as few parts as possible while making it most sensitive. Things like positive feedback AKA regenerative feedback, reflex (feeding back audio through the same tube as RF, where one tube did double duty), and TRF, or Tuned Radio Frequency, which used two or more stages of manually tuned circuits were used. The latter being the most popular. Hence why radios of the twenties had many knobs. One had to tune two to three controls to the same frequency so each stage amplified the same signal a certain amount. This made the radios very sensitive but cumbersome. A few companies tied the three or four stages together so one could use only one knob. But the other negative was that the whole band was not always received well due to inaccuracies with the tuning. In other words, some parts were more sensitive than others.
In comes the superheterodyne. I think it was aroung 1923, Edwin Armstrong (who also invented FM, BTW) invented the circuit where the incoming signal was mixed with a locally derived signal (the local oscillator inside the radio) and a sum and difference signal was created. If the local oscillator was tuned in sync with the desired incoming signal, then the sum and difference signals were constant. This way one can then send either the sum or difference signal through several additional stages of tuned amplification. The difference signal was chosen. Through the early thirties this difference signal could be anywhere from 120kHz to 500kHz. They finally settled with 455 kHz as the intermediate frequency.
So, if you tune to 900 on your dial, the local oscillator was tuned to 900+455, or 1355kHz. Then the two will mix to make 455kHz, and it can be amplified many times by a TRF like circuit tuned only to 455kHz. That is the Intermediate Frequency or IF. So all stations eventually wind up being 455kHz inside the radio.
In your case, there is additional RF, or Radio Frequency (incoming signal) amplification before going throgh the IF conversion stages. Hence why you will hear the first or second tube in a radio called the mixer or converter.
You have what sounds like it is a nice radio. If you can take a picture of it I may be able to help further. I happen to have one that sounds like the same as yours.
Here is a good site with more details and pictures:
http://home.attbi.com/~radiowarren/hetbasic.html
Hope this helps,
Gabe
OK, I read the article for myself and found that Armstrong invented it in 1918. Cool.
Also, as an added note, the reason TRF was more popular was because RCA owned the rights to the superhet and wanted mucho dinero for it. Plus, their own models were more expensive. So, most people settled for single tuned TRF circuits till about 1930 or 31, when the gov't stepped in and said enough of that, it shuld be public domain. Besides, I think that patent rights ran out by then anyway.
As an even more side note, some companies actually sold kits that were superhet, but they clalled it another type of circuit to fool RCA and lawyers.
Gabe
Also, as an added note, the reason TRF was more popular was because RCA owned the rights to the superhet and wanted mucho dinero for it. Plus, their own models were more expensive. So, most people settled for single tuned TRF circuits till about 1930 or 31, when the gov't stepped in and said enough of that, it shuld be public domain. Besides, I think that patent rights ran out by then anyway.
As an even more side note, some companies actually sold kits that were superhet, but they clalled it another type of circuit to fool RCA and lawyers.
Gabe
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