Just Wondering ??
 

Hi All;
I am just wondering.. When I was a kid, I had an AC/DC radio beside my bed.. I don't remember much about it, it was either Bakelite or Plastic case and brown in Color.. The reason I am asking about it.. Is it had a set of Coils for its tuning.. It was made at the end of World War II or with in a few years after that.. I had asked my Dad about why it didn't have a tuning Capicator, and He told me Metal was scarse.. So I am wondering, 1st did all radio manufactures at this time use Coil tuners, or only some manufactures ?? and 2nd of those who did, who are they ?? I had had this radio as far back as I could remember, and when I asked about it, it would have been the late 1960's..
THANK YOU Marty

I have an old AA5 from the postwar era that is otherwise unremarkable, except it has tuning coils/ferrite rods-Sort of a crude R-390 tuning scheme.

That's called permeability tuning. Many designs used it but the vast majority were variable capacitors. I doubt that it had anything to do with scarcity of materials.

Yep, it's also sometimes called inductor tuning. Most car radios had them before the late 50's. I've never read that they were used because of a shortage of metal (copper was scarce too). Instead, I think they were cheaper to make than the gang capacitor. Their main drawback is that they are very delicate and even the smallest deforming of the coil will throw off the tuning.

By far the biggest user of them was a company called Detrola. Look up Detrola 571 on the internet and see if any look like yours. Also, a lot of early FM radios used them too.

"Permeability Tuning" ! That's it ! Had a Mind-Fart there...I wondered why an el cheapo radio would use something like that..Doesn't really work any better or worse than any other AA5 set.

Hi All;
Its not a Detrola..
Also, what is an AA5 set ??
THANK YOU Marty

All-American Five..

Perhaps one of these cute little Airlines... they were very popular. I have one in brown bakelite:
http://www.radioatticarchives.com/radio.htm?radio=204
jr

Are mind farts caused by thinking about beans?

I was also thinking it was war related since I'd seen numerous from 1941-1942 with those tuners including Philco and Silvertone.

No, Mind Farts are caused by the Said Poster-Me- being a bit Senile, & possibly in the 1st stages of Alzheimer's.. Just wait til you get to be almost 56...(grin)

Good Luck on your search Marty...AA5 tubes (octal base) of the era were 12SA7, 12SK7, 12SQ7, 50L6, 35Z5

Mind - fahrt example: I know lotsa tube numbers but please dont ask what I had for breakfast

It might be one of the 50 brand names that Detrola built sets for.
Regarding shortages, Most, if not all of the 571 series receivers had field coil speakers. :scratch2:

Hi All;
I looked in Radio Attic.. I didn't see anything like what I am looking for.. So, either my memory is wrong about what it looked like.. Or they don't have a picture of it.. I saw alot of 40's and 50's radios that I could tell were from that period..
THANK YOU Marty

Ward's sold those both pre and post war. The pre-war model was sold for $5.95, plus shipping. It used a 70L7GT instead of a 35Z5 and 50L6, plus a 12SA7, 12SK7 and a 12SQ7. A full Superhet. The post-war models used the regular five tube line-up.
I saw the four tube model at a swap-meet for $275.00, not restored. :D

Car radios tended to use permeability tuning, and in the early days of WW2 there were some radio makers that made car radios for new production cars, but the car industry switched from consumer cars to military vehicles for the war. Similarly the radio industry soon stopped consumer radio production and started making radio equipment for the military. But there were these now orphaned car radios to do something with, as well as a bunch of radio cabinets without chassises. So they were Frankenset-ed together in production to get them sold to consumers who needed a new radio. Maybe yours was one of these.

Hi All;
I am pretty sure it was not a car radio, turned home radio.. I would say it was about a 5 to 6 tube radio.. I don't remember if it had a transformer or not.. I just remember it was inductor tuned instead of Capacitor tuned, since I had never seen one like it before.. I was going thru Radio repair class and I wanted to know what I had, sitting next to me in my bedroom.. So, I took off the back and looked at the inside..
THANK YOU Marty

Like someone mentioned, I've seen lots of car radios with that tuning set-up but few
AA5's.

Now, many early AM/FM tube radios had this set-up for the FM and a typical tuning capacitor for the AM. In fact, I have a couple Westinghouse models where they bought an FM tuner (inductor tuned) from a company called "Standard Tuner" and incorporated it into a chassis otherwise built by Westinghouse.

I've got a Silvertone farm set with this tuning scheme. It was used in a wide gamut of sets over the years.
If you can remember the cabinet well enough to draw a picture or remember the brand it should make it easier to get an ID of what it was.

As a long shot, look up the Detrola website.
It shows pictures of the many models, that they produced.

Hi All;
I found a picture of a model of a Detrola 571, that is close.. I will try and post a picture of it.. below.. What I had was all Bakelite, brown in color with white speaker grill (Maybe) and had inductor tuning.. But the picture is close enough..

THANK YOU Marty

Attachment 178454

One nice feature of this radio is that the frequencies are nicely evenly spread out across the dial, not with the high frequencies scrunched together on radios using a tuning cap.
http://www.videokarma.org/attachment...4&d=1366728302
The wire on the coilforms of the variable inductors are wound with varied spacing between turns, so that linear movement of the ferrite core will produce a linear change of frequency.

It was worse with the Japanese radios.
There wasn't too many radios that had the dial scale reversed.
Maybe they were planning to use a wavelength scale, instead of the frequency scale. :scratch2: