Vintage Devices – The Gramophone

A month ago, my father and I embarked on a mission to restore our gramophone to working condition. Before detailing the process, allow me to explain a little more about this analog device.

Originally known as the phonograph, it is one of the earliest audio devices in the history of civilization. Thomas Edison introduced this ‘voice machine’ in the late nineteenth century, and was soon seen in the households of the rich and the prosperous.

Eventually, it was discarded, with the adoption of mass produced radios, and wireless broadcast systems such as AM and FM being put to use. However, it is important to know the history of this machine, in order to fully understand the working of audio devices.

The phonograph is a mechanical device that records and reproduces sound. It was invented by Thomas Edison in 1877, with his model capable of storing and playing sound from wax cylinders. A decade later, Emile Berliner patented the ‘Gramophone’, the most popular variant of the phonograph till date.

Note: In this article, I shall refer to the device that plays audio from flat discs as a gramophone, while the device that uses wax cylinders for the same as a phonograph. Since I neither possess a phonograph nor expect my audience to have one, I shall be discussing the gramophone in greater detail. Here’s a diagram of the two devices, side by side:

What makes it spin?

The turntable is basically a metal disc resting on a pivot. The mechanism that rotates it consists of an arrangement of gears, is housed in the gramophone’s wooden box, and uses the energy supplied by a hand crank.

An important part of the driving mechanism is the ‘governor’, which controls the turntable’s speed. This allows it to rotate uniformly at the set RPM (revolutions per minute). The governor consists of a worm gear, to which three weights are attached using steel bands.

The sound box

The sound box is a hollow circular box, with a steel needle attached to its bottom by a screw. Also known as the stylus, it moves along the circular groove of the vinyl disc, generating sound in accordance to the groove’s pits and bumps. The sound box is part of the ‘tone arm’, which allows the stylus to move freely along the groove.

The trumpet, also called the ‘horn’, is seen atop the gramophone, and acts as its amplifier. The device works perfectly fine even without one. In fact, the portable models completely forgo the horn, including cabinet-style gramophones.

Where’s the volume button?

One important thing to note is that this device doesn’t have any volume control. The reason is simple -this device was intended to be used in drawing rooms, especially to play music in the presence of company. It was only after radio receivers began appearing in the market that volume controls came into existence, as a way to amplify weak signals.

Restoration

The first step was to take the machine apart, which involved removing the horn, dismantling the turntable, unscrewing the hand crank, the turntable’s shoe brake and speed setter, and finally retrieving the internal mechanism.

Upon close inspection, it was found that one of the governor’s weights had snapped from its steel band. My father decided to change all the three weights anyway, in order to evenly distribute the governor’s centrifugal force. Besides, it was only a matter of time before the remaining two would snap as well.

For the gramophone’s exterior, the wooden case was sent for repainting. All the brass parts – the horn, the tone arm and the sound box – were cleaned up with Brasso. The RPM setter and the braking shoe had a thick layer of rust on them, which had to be scraped off using emery paper.

The restoration efforts seem to be worth it, as the gramophone is now in working order. See for yourself!

Let’s play some music!

The only vinyl discs we have run at a much lower RPM – about 33 to 45 RPM. This is unfortunate, since the gramophone we restored has a range of 78 – 86 RPM. Hence, the discs play at about double speed, making the vocals stored on the records sound like squirrel squeaks.

Here are the vinyl discs, which I attempted to play:

The first record has 2 songs from the film Padosan(1968).

The second record has 3 songs from the film Aandhi(1975), despite being smaller in size.

We had many more discs – probably a dozen of them – which were smashed to smithereens by yours truly in her childhood.

Hopefully, we shall acquire a few more vinyl discs in the future, which are fit for playing on our gramophone.

Related links

Record players and phonographs; an article:

http://www.explainthatstuff.com/record-players.html

The invention of vinyl records; an article:

http://eil.com/explore/guide/vinyl_invention.asp

How Does the Gramophone Work; a forum post:

https://www.reddit.com/r/askscience/comments/20peit/how_does_the_gramophone_work/

How Records Are Made; an article:

http://gizmodo.com/5987010/how-records-are-made

“Bob Maffit – Phonograph Restoration” (2000); a video:

https://www.youtube.com/watch?v=_1NZReuYdco

Electron microscope slow-motion video of vinyl LP; a video:

https://www.youtube.com/watch?v=GuCdsyCWmt8

Stereo Records vs. Mono Records; an article:

http://www.rarerecords.net/stereo-records-or-mono-records-which-one-to-buy/

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