They Don’t Make Them Like They Used To

For those of us that grew up in a world where the transistor had already completely reshaped the world of electronics, the gadgets that were created before this time often seem very foreign. Sam Battle, better known as Look Mum No Computer, came across what is now an oddity of this sort — an old church organ from the time between when organ pipes resonated with pressurized air, and today’s modern, transistor-based instruments. It is strange indeed, but quite interesting to learn about all the same. And in Battle’s recent video, we get a tour of this huge and mysterious machine.

In particular, Battle came into possession of a church organ tone generator. This is the part that would be hidden in a basement or back room, out of view. The console — that is, the keyboard, foot pedals, and so on, that the musician plays — was missing. After studying the machine for a while, and consulting with some individuals that are knowledgeable about it, it was found that a set of 36 spinning discs serve as the tone generators. When powered up, each of these discs is driven by a single belt and motor.

To help understand what makes them tick, Battle disassembled one of the tone generators. Inside, etched on the back plate, was a series of sine waves of differing octaves. Opposite this back plate was a spinning disc, with areas of raised and lowered edges that match up with the sine waves on the back plate. This forms an electrostatic tone generator — as the distance between the surfaces changes, so does the distance that electrons travel between them. This produces a modulated signal at the output at an audible rate.

One of these tone generators was hooked up in isolation to demonstrate the interesting, and sometimes eerie, sounds that they can make. After returning it to the machine, it was explained that the machine is broken up into a tone generating rack, and another rack that interfaces with the missing console. If the console was present, each key press would send a 24 volt signal down one of about 400 wires.

That would, in turn, trigger a relay and a group of the 700 or so wires that feed back into the tone generator. And that would cause some subset of the tone generators to do their job. Finally, the output of all of the tone generators is combined into a single channel that can be amplified, and that is the final output of the organ.

While the console was nowhere to be found, the machine does have a test bay. Each test point can simulate the press of one key or pedal on a console. So, using this, Battle showed what the organ can do. Well, sort of. With just a few alligator clips you can’t exactly expect Beethoven. But as a next step, Battle may wire some type of keyboard into the system. Be sure to check back in soon to see if this project materializes.