Mid '30's "talking book" record player

[radiotvnut]

Here's an American Foundation for the Blind "talking book" record player, model U-10, that I believe is the very first model of talking book phonograph. This machine plays 33 1/3 rpm (talking book speed) and 78 rpm (music) records. This model also has a built-in AM radio that uses a TRF circuit. It's interesting to note that this model uses two volume controls. One is for the phonograph and one is for the radio. I think the phono volume control is in the audio circuit and the radio volume control is in the antenna circuit.

This thing uses a heavy tonearm and a horseshoe magnetic cartridge that tracks heavy enough to cut a new groove in a record; so, this will obviously not work with microgroove records. It's my understanding that the first TB records were pressed on some sort of plastic; but, they used they same type of groove as a 78 rpm record. I have some later 33 rpm TB records from the '50's; but, they are microgroove and are designed to be played with a much lighter tonearm. According to the instructions, this machine can also play British 24 rpm TB records by moving the pitch control to it's slowest position. The instructions also caution that the British records are made of shellac and are easily broken.

This should still be an interesting restoration project and it certainly has it's rightful place in history.

Actually, I'm a user of the talking book service and I'm a collector of these vintage TB machines.

The best TB players were the wooden cased tube models from the '60's that played 8, 16, and 33 rpm and used an Astatic powerpoint plug-in cartridge (like what's in the school califone record players).

Here's a video I made of the inside of the machine:

http://www.youtube.com/watch?v=5utnGAbCpIA

[bob91343]

I thought those used 16-2/3 rpm. If not, then what did?

[radiotvnut]

From '34 until the late '50's, all library of congress TB's were 33 rpm. In the late '50's, the LOC introduced 10" 16 2/3 rpm rigid disc records. By '62, all TB's were issued on 10" 16 2/3 rpm records. By the mid-late '60's, some talking magazines started being recorded at 8 1/3 rpm. By '73, 8 1/3 rpm became the standard speed for all library of congress TB records. By this time, some books were recorded on 10" rigid disc as well as 9" flexible disc. Talking book machines made between '65 and the '90's played 8, 16, and 33 rpm. The LOC converted it's last round of magazines from flexible disc to cassette by the end of 2000.

[bob91343]

In all my years, including 13 years repairing at retail, I have never seen a record player for slower than 16-2/3 rpm. Very interesting!

[dieseljeep]

The schematic is in Riders #7. They show three different models. The TRF with the three gang tuner must've worked pretty well. They also show a transformer powered model. I don't think they used a line cord resister, on a unit built for the LOC.
I saw the u-tube video on it. The speaker has a Fada nameplate on it. I wouldn't doubt that they built it. The one one the video has a newer standard line cord on it.

[radiotvnut]

I never even thought to look this up in the Rider's index because I figured there would not be a schematic available for it. Thanks for bringing it to my attention and that schematic may come in handy when I work on this thing.

[dieseljeep]

Originally Posted by radiotvnut

I never even thought to look this up in the Rider's index because I figured there would not be a schematic available for it. Thanks for bringing it to my attention and that schematic may come in handy when I work on this thing.

After looking at the schematic, the "u" model is some kind of an early superhet. It looks like another form of an Autodyne converter.
They list a 175KC IF frequency.

[radiotvnut]

Originally Posted by dieseljeep

After looking at the schematic, the "u" model is some kind of an early superhet. It looks like another form of an Autodyne converter.
They list a 175KC IF frequency.

I noticed that after paying closer attention to the schematic; but, looking at the chassis from the top would sure make one think that it was a TRF set.

[dieseljeep]

Originally Posted by radiotvnut

I noticed that after paying closer attention to the schematic; but, looking at the chassis from the top would sure make one think that it was a TRF set.

That long coil must be part of the IF circuit. One section of the tuning gang is some kind of a pre-selector circuit.
Interesting to say the least.