Nixie-based tube clocks

Price $164.99, including shipping

Manufacturer: Millclock

Millclock are based in Ukraine and offer a range of assembled clocks and thermometers, as well as some kits. We're going to focus on an assembled clock in this review, which is one of the more simple clocks available from Millclock.

One point before we start about the kits: There's been some negative press about the kits, but you should take that with a pinch of salt; The complaints were that the assembly was difficult because the components used are SMD (Surface Mount Devices), but that's entirely clear from looking at the pictures on the site. The complaints are a little unfair, and the Millclock site states that there is some assembly skill needed.

However, we're talking about a fully assembled and tested item in this review: The IN-12 Nixie Tube Clock With Walnut Wood Enclosure.

Walnut IN-12 


Ordering, delivery, unboxing

The package arrived quickly from the Ukraine; the shipping costs part of the price, and the priority postage that Millclock uses means that you won't have to wait very long for the clock to arrive. The clock itself was well packed and in perfect condition, well padded with polystyrene against the worst that a postal service can do. Inside the box, there was a power supply, the clock unit, and a very short instruction sheet, which covered half a side of paper. Clearly there isn't a lot to configure in this clock.

A 12V 1A power supply with a EU plug on it was in the box, and all you need to do to get the clock going is to plug it in and set the time! Very easy indeed.


Overall impressions

The clock is very small, and is quite a triumph of miniaturization. The front panel is barely larger than the 4 IN-12 tubes, and the depth of the unit front to back is slightly larger than the height. There are two buttons on the top of the case, and a small hole in the top. This is for cooling on the pre-production unit, but will be removed for the mass production, because the clock does not produce very much heat. 

The case is entirely in wood, and nicely finished, with an etched logo on the back panel, which  is a nice touch. The rounded corners and the grain of the wood give the clock a nice feel. The unit is comfortingly heavy in the hand. In the front between the hours and the minutes, there is a single small neon indicator.

The unit measures 113mm wide, 44mm high and 44mm deep, and weighs about 160g. The new international Nixie measurement standard of a 100g Toblerone, which is 210mm, so that means that it's just over 0.5T wide in the new units.

There were a couple of slight problems in the final assembly of the case, but I think there are because the unit I have is an early pre-production model. They are not very serious problems: The back panel is glued on, and it does not look to be easy to change the battery. Some screws would have been a better solution, because eventually the battery will need to be replaced.

Also, on the review unit, the power lead is very short, it is only xx cm, and this means it's sometimes difficult to find a good location for the clock close enough to a power outlet. The power adaptor is glued directly into the case, and it's not possible to change it. The application of the glue was not very pretty.

Operation of the clock is quite straightforward, justifying the single page of instructions. It covers all the normal functions of a small clock. You can set the time and date, you can set the time format to 12 hour or 24 hour mode, you can turn on or off the back light, and you can set whether you want to have the date displayed. It's that simple!

Clearly, inside this clock there is a small SMD PCB which holds the electronics and the tubes. Measuring an IN-12 against the unit we can see that it looks like the tubes are mounted directly on the board, and that is not going to leave much room for electronics. My statement about the miniaturization seems to be true. 



The operation is super simple, and it's perfect for a small, easy "fit and forget" clock that you might keep in an office or a bedroom. The left hand button is the "menu" button, to move between menus when you are setting the clock, and the right hand button, adjusts the setting, or shows the date when you are in normal time mode. Each time the date is shown, the display does a little scroll through animation, which also serves as a rudimentary anti cathode poisoning.

The menu is easy to understand. First press the "menu" button (the left one), and the neon stops flashing. This is an indication that you are in setting mode. Then you can press the "adjust" button (the right one) to change the settings. After you have set the hour, press the "menu" button again to move onto the minutes, and again you can press the "adjust" button to set the minutes. When you move onto the minutes, the neon stays on. This is the clock's way of telling you that you are in setting mode, and you are working on the right hand pair of digits, in this case, the minutes.

Pressing the "menu" button again takes you into the date settings. The neon is off, so we are working on the first two digits, which is the day of the month. Set this, and then press the "menu" button again, and the neon shows us that we are looking at the right hand digits, which is the month.

Press the "menu" button again, and now we move onto the year. The next option is the 12 hour or 24 hour mode. "00" means we are in 24 hour mode, which is the default, and "01" is 12 hour mode.

The next pair of options is the back light which can be "01", meaning back light on, which is the default, or "00" meaning back light off. It would be nice if the back light was turned on or off when you change the setting, but it only sets the back light LEDs once you exit the settings mode. The next setting is whether to show the date by default. This means that every so often the date will be shown automatically. "01" means show the date (the default) and "00" means do not show the date.

You will notice that there is no option to set the seconds, because this is done automatically when you exit settings mode. When you finish the setting up, the seconds are set to "00" automatically. 

IN-12 tubes are super robust, so the anti cathode poisoning isn't really that necessary.

The time is battery backed, meaning that if you turn it off, it still keeps time perfectly. It's not using something like a super-capacitor, which will keep the time for a few minutes, it has a battery so that it will keep counting time as long as the battery runs, and the life of these batteries is usually measured in years. Millclock tell me that the life of the battery is rated as 10 years.



Millclock LogoThis is an excellent tiny little clock, pretty much the smallest enclosed clock that you can make with the hardy IN-12 tubes. It doesn't have a lot of functions, but the ones it has are dead easy to use, and cover what you want for a clock in an office or a bedroom. It has all the beauty of Nixies, in a small, modern package, with a high quality case. I think it's a little pricey for what it is, but bear in mind that the cost includes priority shipping and some high quality materials.

There are one or two little finishing touches which it would be nice to take care of (the glued back to the case and the missing strain relief around the short cable), but apart from that, it's a high quality, uncomplicated, accurate clock.

There is also a "dark chocolate" version available.

The guarantee is 1 year.

All in all, a nice little clock. 



There is also a tear down of the clock. Bear in mind that this is a pre-production version of the clock, and the electronics looks pretty complete, but there are a few little rough edges in the case and construction. The teardown video is here:


Is this (click on the image to see the full resolution picture of the madness):


KABTronics TubeClock


I'll be testing myself against it in a fight to the death:

  • 215 Transistors
  • 518 Diodes
  • 472 Resistors
  • 101 Capacitors
  • 10" x 14" Printed Circuit Board with silk screen symbols indicating component locations

Who will win? (My money is on the clock).


KABTronics web site


Single Digit IN-18 Nixie Clock

Under my desk there is a box of IN-18 tubes which I have been meaning to use for a while, some of the tubes are perched on the top of the box, threatening to fall out, and it really way time to do something with them. Browsing EBay lead me eventually to the fantastic array of gadgets on the site, and I just had to have one of the cute, beautifully designed Single Digit Nixie clocks that would fit with a tube from my overflowing box.

The ordering process went beautifully, and the assembled clock arrived within 2 weeks, well packed and in a small but sturdy cardboard box. The clock comes without a tube, but the process of fitting a tube is really straightforward, because there are pin sockets which seem to fit snugly, but without the idea that you are forcing the tube into the socket.

Single Digit IN-18 Nixie Clock as delivered

One of the beautiful things about this little clock is that it needs only a USB 5V supply to make it run. It is quite power efficient, and doesn't consume much energy, and doesn't get hot. While diplaying the time, it shows the tens or hours, hours, tens of minutes and minutes one after the other. To help you understand the time more easily, the single hours and single minutes also light up the right hand neon bulb as well.

Setting the options is a bit fiddly. Personally I had a bit of trouble understanding the menu structure, and had to keep reading it attentively to be able to set the clock, but that is the cost of having a clock with only a single digit and lots of options. Once the clock is set, you won't have to set it again very often, because the time is preserved by a battery driven Real Time Clock when there is no power. The time keeps counting even when the clock is turned off. You can see the data sheets in in English or in Chinese.

179 EUR (Kit) & 50.34 EUR (Tubes)

Welcome to the Black’n’wood review. I’ve reviewed several other Nocrotec clocks before and this one comes to us from a combination of sources. Dieter of Nocrotec worked with YanZeYuan (严泽远) to develop the electronics for this device. The tubes are sold by and the kit components are sold though

The first thing that you notice is that this device uses end view tubes. The default set are  Chinese QS30-1 tubes. These are uncoated tubes with proper 5s and 2s. These are 30mm diameter tubes that use a standard base. Consequently, there are multiple tubes that can work as substitutes. For example, I have swapped out my tubes for the orange-coated GN-4 tubes (more on this later). Nocrotec has a list of substitutes that I have included at the bottom of this review for reference.

While we’re on the topic of tubes it is worth talking about viewing angle. Side view tubes typically have a wider viewing angle (both vertically and horizontally) than end view tubes. On end view tubes, the digits are stacked on top of each other in a small cylinder. This means that the numeral 9 is easier to see than a 6 because the 9 is at the front of the tube and the 6 is at the rear (digits are not stacked in numerical order). This clock is no exception. Because of this, the clock will ideally be mounted somewhere around eye level. I don’t consider this a problem because it is the nature of all tubes like this.

The enclosure clearly follows the design of some of the original Nocrotec clocks. The wooden base and metal plate look nearly identical to my X2000 []. I am a huge fan of this design; it gives the clock a nice luxury feel. The case itself is 287mm wide, 49mm deep, and 75mm tall (11.3” x  1.9” x 2.9”). The tubes protrude slightly but only by a few millimeters.

A small feature that I wanted to call out is the colon indicator tubes. They are not led; they are tiny neon bulbs. This was done to match the color of the nixie tubes but it also gives the device some subtle detail. For example, the top of the tubes are crimped and this causes the light pattern to be different from any led bulb. The tubes flicker somewhat; you can see the flow inside of the tube bouncing around. You don’t notice these details at first but when you start staring at them you quickly appreciate them.

The tubes are illuminated with blue LEDs which fade on/off every two seconds by default. You can order other colors (ocean green, deep green, white, purple) and if you don’t like the backlights, you can simply disable them. Earlier I mentioned that I swapped out the tubes with orange-coated GN-4s. The tubes are surrounded with foam padding to prevent light leakage from around the tube. With this surround and the orange coating, the backlight is almost completely blocked. Considering that orange and blue are opposites, this is not really surprising but it does mean that if you want to use the backlight feature, you should stick to uncoated tubes.

Keeping track of the time can be done a few different ways. The device comes with an internal crystal so you can simply set this clock like any other and let it run. You can also use a GPS receiver or a DCF77 receiver to set and maintain the time. The DCF77 and GPS options are external devices that you can purchase at a later time. Enabling them is as simple as changing a menu option on the device.

There is another interesting feature that may be of interest to some users. The Mini DIN connector can be uses to switch con and off other devices when then alarm sounds. You will need to add a relay to switch anything but the +5 V output may be interesting to some users.

Overall, this is a solid design. It offers a robust feature set and looks nice at the same time. I’ve been able to play with this clock for a few weeks and I thoroughly enjoy it.


Black'n'Wood Nixie Clock

Black'n'Wood Nixie Clock

Black'n'Wood Nixie Clock

Black'n'Wood Nixie Clock

Black'n'Wood Nixie Clock

Black'n'Wood Nixie Clock

Black'n'Wood Nixie Clock

Black'n'Wood Nixie Clock

Black'n'Wood Nixie Clock

Black'n'Wood Nixie Clock

Tube substitutes

10TU26, 122P224, 154-0327-00, 1970-0002, 5031, 50347, 5037, 5092, 5092A, 6770, 6844A, 8037, 8037(B-5031), 8421, 8421(B-5092), 8421/5092, B-5031, B-5031/6844, B-50347, B-5037, B-5092, B-5092/8421, B-5092A, B-6844A, BD-302, CD102, CD18, CD24, CD26, CD32A, CK6844A, CK8037, CK8421, CV5278, CV9316, CV9732, F9057, F9057A, F9057AA, GN-3, GN-4, GN-4A, GN-4D, GN-4E, GN-4P, GNP-4A, GR10M, HB-106, JAN-6844A, JAN-8037, JAN-8421, JAN-CB-6844A, JAN-CZ-6844A, LC-511, LC-513, LC-513A, M2726-102500, M2726-102600, NE-50347, NL-5031, NL-50347, NL-5092, NL-6844, NL-6844A, NL-8037, NL-8421, ST12C, SZ1-1, SZ3-1, SZ-8, Z510M, Z520M, Z5600M, Z560M, ZM1020, ZM1020/01, ZM1022, ZM1022p


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