What is a Nixie Tube?
Nixie tubes are a Cold-War-era gas-discharge tube that is used to display characters, in our
case numbers 0-9, but other types were made too. Each character is formed from bent wire
(known as the cathode) and arranged in a stack, with a wire mesh at the front of the tube
forming the anode. These tubes are then filled with neon gas, and when a DC high voltage is
applied to its terminals, the corresponding character lights up orange. These tubes are
known as cold cathode devices and will run only slightly warm to the touch. The tubes are
essentially complex neon bulbs, which is why the orange glow exactly matches that of the
more familiar neon bulb colons used in our clock colon. In the photo to the right, you can
see the wire mesh and the stacked digits. Note how the numbers 0 and 6 appear at the
back/front of the tube respectively due to the digit stacking. The two stacked bulbs used in
our clocks as the hour/minute separator colon is shown to the left - it has the same colour
glow as the numbers, because they both use neon gas discharge to create the light.
Nixie tubes are most associated with Soviet technology, but many countries produced these tubes when they were popular.
Nixie tubes are most associated with Soviet technology, but many countries produced these tubes when they were popular.
NIX labs Nixie clocks use “IN8-2” (aka ИН8-2) tubes in the upright NIX4 and NIX6 models,
and the front-view “IN12” (aka ИН12) in the NIX4F design - all are authentic Soviet-made tubes. Both tube
kinds have the same large, bright, orange digits, however the IN8-2 uses a fully formed “5” digit whereas
the IN12 uses an upside-down “2” instead as a cost-saving measure.
The photo on the left shows a comparison of the IN8-2 tube (left) and a the IN12 (aka ИН12) tube (right), the latter which uses an upside-down 2 as a the 5 digit.
The photo on the left shows a comparison of the IN8-2 tube (left) and a the IN12 (aka ИН12) tube (right), the latter which uses an upside-down 2 as a the 5 digit.
These tubes have not been made for many years, and the ones used in our clocks are generally
40-60 years old. Nixie tubes were especially popular in scientific and industrial equipment
such as control panel readouts, benchtop multimeters and early calculators. These tubes are
now finding a second life in our bespoke clocks, and it is fascinating to think what purpose
each tube had originally.
You can generally find the date of manufacture on the back of the tubes. Wherever possible we try to preserve the original factory markings on the tubes, but sometimes they flake off or are removed easily during cleaning.
The photo on the right shows two tubes from the same manufacturer, MELZ Tube Factory in Moscow, Russia (signified by the “M” in a circle logo). The left tube has a marking of “1189”, so November 1989. For the older tube on the right, there is a month code in latin numerals (“IV”) to the left of the M logo, and “73” to the right, meaning April 1973. Most Soviet Nixie tubes repurposed today span this 1970s to 1990s vintage.
You can generally find the date of manufacture on the back of the tubes. Wherever possible we try to preserve the original factory markings on the tubes, but sometimes they flake off or are removed easily during cleaning.
The photo on the right shows two tubes from the same manufacturer, MELZ Tube Factory in Moscow, Russia (signified by the “M” in a circle logo). The left tube has a marking of “1189”, so November 1989. For the older tube on the right, there is a month code in latin numerals (“IV”) to the left of the M logo, and “73” to the right, meaning April 1973. Most Soviet Nixie tubes repurposed today span this 1970s to 1990s vintage.
