The First Amplifier Ever Ran on Compressed Air…

Charles Algernon Parson, a turn of the previous century Anglo-Irish inventor, was certainly one to think outside the box. An expert in steam turbines for ships and generators he eventually ventured into the world of audio reproduction in the early 1900’s. Unhappy with the sound level produced by early phonographs, and many decades before having access to any tube valve amplification systems, he decided to go about and fix this problem in the most unusual way: As shown below he used compressed air to amplify sound.

In 1906, when shellac records were just about to replace the previously used wax coated cylinders, he presented the glorious yet hard to pronounce Auxetophone produced by the company Victor to the masses as a commercial product available for the handsome amount of 500 dollars long before anyone had any notion of what audiophile was and how anyone could come to spend what would be today’s equivalent of a price for a small car for something that merely reproduced sound. 

The reason the Auxetophone was an immediate success was because it accomplished something that a lot of successful machinery accomplished after the onset of the industrial revolution: It allowed people to fire other people. In this particular case the ones who were ousted were musicians form small orchestras in dance halls around the US and the world who were simply replaced by a rather audible Auxetophone.

The operating principle of this incredible device is as simple as it is brilliant. A turbine was used to compress air stored in a small tank. At the core of the contraption was a sound box that contained a diaphragm that in turn was attached to a reed valve, which finally was connected to a gramophone needle.

As the needle moved, the reed valve moved accordingly allowing more, or less compressed air to flow out the valve and through a compression horn reproducing the sound of the record reasonably accurately but many times louder.

So obnoxiously loud were they in fact that most Auxetophones were sold to be used in outdoors events and very large restaurants.  It was even loud enough to overcome the already very loud electric blower used to compress the air. Very few were sold to private residences and if they were then installed in homes, these homes must have had rather large rooms.  The one thing they really didn’t have, you see, was a working volume control. The intuitive choice to lower the pressure to lower the volume did not work very well. As a result all Auxetophones were supplied with a standard issue gramophone sound box which would let them operate without compression and thus also without the use of electricity, albeit at normal gramophone volumes.

The days of the Auxetophone were of course numbered with the invention of the thermionic valve amplifier in 1904 and the first triode in 1906. Those developments were largely driven by the growing telephone industry that was craving larger and larger distances to be bridged. The same industry was also driving the development of the electromagnetic loudspeaker driver and it did not take long until someone figured out how to piece the two together and play music. More on that perhaps another day.

If you would like to know more about this incredible machine, I highly recommend you visit the site that dedicates itself to keeping its story alive.

Arved Deecke is founder of the Danish / Mexican Loudspeaker company KVART & BØLGE that makes audiophile quarter wave loudspeakers and sound systems at a price anyone can afford. In his free time he blogs about all things related to sound, music and audio.