[R Radbill]

Hello: Is there anyone here qualified to check out a transitone model 3 Automobile radio. Outward appearance looks good but power supply is unknown. There does not seem to be a B eliminator but the remainder appears to be complete and not damaged.

[fenbach]

Is this the radio you have?    
https://philcoradio.com/library/index.ph...to-radios/

[R Radbill]

Yes, exactly, thank you.

[fenbach]

I think you'd want to have the B+ power supply on hand before investing much in a repair/restoration. Either that or plan to have a vibrator, high voltage transformer and rectifier unit made. Maybe even hidden inside. Or "borrow" one from another radio.
Here's a link to more information about the radio

https://www.radiomuseum.org/r/philco_3.html

and the schematic

http://www.nostalgiaair.org/PagesByModel...013183.pdf

Any idea what make of car it came out of?

[MrFixr55]

Edited 05/21/23) I believe that this radio was aftermarket, therefore found in many cars such as the Ford Model A and its competitors. It did not come with a power supply. It was a TRF unit that used 3 24As as RF Amps, a 71A (???!!!) as a detector, connected as a diode using the cathode and grid. The plate was grounded and acted as a shield. A 01A served as the AF Amp and a 71A served as the output. The 24A filaments (2.5V) were in series. There were dropping resistors for the 2 71As and type 01A. The tube filaments ("A" Supply) ran off the car's 6V battery / generator. For this and other early auto radios, the B supply was from four 45V B Batteries in series. There was no C battery, there was a dropping resistor in the negative circuit to get the C-. To get B+ without using batteries, a motor generator or "Dynamotor" was used, or one could buy a Mallory vibrator power supply.

This radio was circa 1930-31. A 71A put out a whopping 0.7W of audio. I can't imagine the filaments of the 71As and 01A in this radio lasting a real long time. The '33 and later Ford Model B V8 had a factory radio available that was built by Grigsby- Grunow (Majestic). It used 39s for RF and IF Amps a 38 (???!!) as an autodyne mixer, 38s in Push Pull for Power Amp and an 85 Detector AVC and 1st Audio, and a dynamotor for the B supply. In 3-4 short years, Auto Radios substantially developed into circuits very similar to home radios, with built in B supplies, either by "synchronous vibrator" or by a much simpler vibrator and rectifier. A lot of this credit goes to Philco (and Sylvania their tube supplier?), and possibly RCA (or not, but they just took credit?) for developing the 42, the first power pentode with heater / cathode instead of a filament cathode (developed before RCA's 2A5, the replacement for the '47), and some other 6V tubes such as the 77 (replacing the 2V 57), the 78 (replacing the 58), the 6A7 (replacing the 2A7), etc. Other 6V power Amp tubes such as the 38 and 41 followed(I am not sure when the 6A4 / LA was introduced or by who. Philco was also an early pioneer for using 6V tubes in their home radios, before RCA, Zenith and others switched from the 2.5V versions, even switching from the 80 to the 84 rectifier with a 6V heater and tubular cathode, thereby eliminating a winding on the power transformer.

In just a few short years (1933-1934), Philco introduced the Transitone 10, a thoroughly modern 6 tube circuit with 44 remote cutoff (super-control) pentode RF, 2A7 pentagrid Converter, 44 IF, 75 Detector / AVC, 1st AF Amp, and single 42 Output. Power Supply was by asynchronous vibrator and 84 full wave rectifier. Other than Push Pull Output (and not all newer radios had push-pull), reactance pushbutton tuning, signal seeking and newer style tubes, this radio had everything that a tube type car radio had, all the way to the the introduction of all transistor radios in 1958-1963.

If you are interested, search Nostalgia Air for Ford and Cadillac radios for interesting circuits and the evolution of Car Radio. I wonder if anyone did a comparative chronology of car radios showing the evolution from the Transitone 3, through Superhets, through In Dash, inductance tuned, push button, "transistor powered" w/ space charge tubes to all transistor to the high tech radios of current production. Have to include the Chrysler "Highway HiFi" record player, Lear Jet tape players, 8 tracks and cassettes.

I think that this is a seminal radio and historically important. If I had a Ford Model A, I would have this in it!

[R Radbill]

Thank you for this detailed reply. The set was originally installed in a new 1931 Lincoln limousine which I am hoping to reinstall as all the mounting holes are still present and would be vacant without it. The car was delivered with the antenna installed at the factory to Philadelphia Lincoln dealership. So far, I have not seen any power supply parts but will photograph what remains that has been boxed up for years but thankfully saved.

[radiorich]

Hello R Radbill,
Wow, that sounds really cool what a great car and hopefully you can get the radio working again !
I am looking forward to see the photos .

Sincerely Richard

[MrFixr55]

Hi R Radbill, 

Wow, a 31 Lincoln!  Model K, KA, KB?  V8 or V12?  A really cool car (I am prejudiced I have a pathological love for Fords, Mercs and Lincolns).  If the B Supply was by batteries, they would be in a box either under the back seat or under / through the floorboards.  Vibrator or Dynamotor supply would be in the same area (?).  I have read through several installation instructions for radios of this type and have not seen anywhere where it was recommended to installed a battery box, vibrator or Dynamotor in the engine compartment. This should be a rather quiet car so at least the radio can be heard.

This is a TRF set, should be rather easy to restore.  A transformer with 120V primary (used as the secondary) and 12V center tapped secondary (used as primary) a, full wave solid state rectifier and vibrator can be used to build an appropriate "B" supply using the schematics of later radios.

[R Radbill]

Thank you for your reply. I am not a radio expert. I have made a dynamo run in a 1930 Packard and tested the output with six volt input. It ran quietly and made amazing voltage but never hooked it up to its’ PHILCO Transitone model 7 receiver. I would not know where to find the appropriate power supply for the Transitone 3. Are there some possibilities for a modern workable power supply or are there original parts somewhere?

[R Radbill]

I perhaps missed what was stated about a full wave solid state rectifier……In 1931 the only Lincoln was a Model K V8.

[MrFixr55]

Hi R Radbill,
Thanks for the info on the '31 Lincoln. I am much more knowledgeable on later ones. My bucket list project is a 1964 Lincoln Continental convertible. 4 doors, the rear being suicide. The ragtop does not store behind the seat, the trunk opens backwards, the top unlocks and retracts into the trunk, a small cover flap extends, and the trunk lid closes, all from one toggle switch. There is as much room in the rear seat in these convertibles as there is in in the sedan model.

Regarding your Transitone 3, you have the same options to power it now ad the original owner did in 1931, either by battery, dynamotor or by a Mallory Elkonode "B Eliminator", a vibrator type power supply that later became the standard for car radios until transistorized radios appeared. Since you need 20 9V batteries to get 180V and they would likely last 10 hours or less, (A 9V Type 1604 transistor radio battery is rated for 500mAH and this radio likely draws about 30 mA B+ Current) this is not economically feasible. AA batteries are rated at 2200mAH and would be more feasible, as you
would get about 80hours. However, the batteries and holders would surely add up.

If you have another dynamo similar to the one used with the Transitone 7, it may be useable with the Transitone 3. The output voltage should be between 150 and 190V (Spec is for 180V.) Dynaotors and Mallory Elkonode B Eliminators are very rare nowadays but you may get lucky.

What I was getting at is that a "vibrator" style supply can be built with either a vintage or solid state 6V vibrator, a transformer, capacitor and solid state full wave bridge rectifier. For the purpose of testing the radio, you can hook a whole bunch of 9volt transistor batteries in series. It won't play long but it will play. Currently, I have no drawing program for electronics and have no way of scanning a hand drawing into a computer. If an Expert can draw this, you may be able to assemble it or have someone else assemble for you.

[R Radbill]

Thank you, I will try to get photos this week of what is there.

[Antipodal]

Hi everyone, I notice on this thread that Mr Fixr55 asks ,in an earlier post if anyone has done a comparative chronology of the development of car radios.Perhaps you already know of this book but if not you will find this an excellent read which will provide just the comparative chronology you seek. The book is called "The Auto Radio - A romantic Genealogy "written by one of your fellow Americans ,one Donald W. Matteson.I got my copy ,second hand of course ,last year from the U.S.A. ISBN 0-944167-00-4.

[klondike98]

Thanks for adding that Auto Radio book reference!

[wannchev]

A great read. Thanks everyone