Humming Along: The Bulova Accutron

There is a fantasy sub-genre called “Transistorpunk” but it doesn’t seem to be that popular. Unlike the charming Vernian pseudo-Victorian creations of Steampunk artists I can’t find anything constructed of multi-color banded resistors or staid black and silver transistors popping out of stiff green circuit boards. That era, where being able to carry a radio seemed like a technological miracle, must not stir imaginations as much as the gilded age. Still, I doubt even if a t-punk tried that they could beat the oddness of the Bulova Accutron Spaceview shown here.

I’ve always had a soft spot for the world’s first all electronic watch. My father wore an Accutron and as I was growing up hearing the soft hum of the tuning fork against my ear was comforting in some way. Certainly it was one of the oddest and most unexpected noises to ever come out of a wristwatch. The story of the hum is really the story of the Accutron itself.

It was what many people consider the greatest invention of the 20^th century, the transistor, which made the Accutron possible. In 1953 a Swiss engineer named Max Hetzel took an early low-power CK 722 transistor and used it to keep a turning fork vibrating at a constant rate electro-magnetically. The newfangled transistor not only allowed for electricity to create a magnetic field which at just the right moment gave a little push to keep things moving but also the unbelievable (for the time) compact size. Working for the Bulova watch company he designed the first production tuning fork movement, the Accutron Caliber 214 (used in the watch here). For the next 17 years they improved the technology making the movement simpler, smaller, and more accurate. This technology was also licensed to more prestigious Swiss watch firms who came out with their own models.

So how does it work with a tuning fork? It’s the same basic principle as any other time measurement device: Watch and clock mechanisms use a reliable repeating event to allow them to track time. Much like how a day can be marked from sunrise to sunrise a swing of a pendulum or the oscillation of a quartz crystal reports to the greater mechanism the passage of one unit of time. If you know how many of these discrete events add up to a second, congratulations, you’re a watch or clock! In the Accutron a tuning fork that resonates at 360 times per second (360Hz) is the heart of the watch. The byproduct of this is the emission of an audible frequency like the tuning forks you might have played with in music class as a child (but not quite as pretty sounding).

One of the most prized versions of this watch is named the Spaceview. Calling it that evoked the US space program even though this watch never went into space (as the Omega Speedmaster did). It wasn’t all marketing, though, since the watch movement was used as instrumentation on equipment that went to the moon. Spaceviews have no dial but a straight “view” to the front of what was the most advanced personal technology you could have in 1961. What is called a “chapter ring” is on the outskirts of the exposed movement and gives you some idea of what the hands are indicating. The tuning fork is right out front with its base at the 6 o’clock position and the tines flanking the 12 o’clock locale. A few other nifty things like the gear train, transistor, resistor, and a capacitor catch the eye. All this on a weird turquoise plastic background! It’s both period and pretty (to a geek).

Advancements in this technology ended with the introduction of low cost quartz watches. The crystal in these could vibrate at 32,768Hz at lower power draw than the Accutrons. The advantage of accuracy, lower production costs, and longer battery life brought an end to the wonderful and unique saga of the watch that hums. Well, not for me. I’m keeping the ones I have going if only to hear them sing once in a while.