Nixie-based tube clocks

by Turbo_Hobby

Price: ~ $48 USD / eBay buy-in-now

SZ-8 Nixie Clock


I just got my SZ-8 clock in the mail and I am excited to review it for you.  Shipping from Singapore took about two and a half weeks but that isn't too surprising considering that it had to clear US Import Customs.  (I originally posted about the clock here. )

For disclosure, this clock was not sent to me for review.  I discovered it on eBay by accident and purchased a unit for my own collection.  All of the photos and video in this review are mine.

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One of the stand out features of this clock is that it only has one digit.  That might be an obvious statement but it is a little unusual.  The time is displayed by displaying the digits in HHMM order.  There is a brief pause between the numbers and a longer pause once it is finished.  You can see this in the video.  To make reading easier, there are four yellow LED's which indicate which digit is being displayed.  While I have only had the clock for a short while, I already prefer having the yellow indicators on.

SZ-8 Nixie Clock

Setting the clock is a bit of a pain.  This is primarily because it didn't ship with any instructions.  When the clock first powers on, it displays every digit once, presumably as a power on self test.  Once that is done, the LEFT button turns on and off the yellow indicators.  To set the time, turn on the yellow indicators - this will make your job much easier.  The clock has already started cycling through the digits.  When it gets to a digit you want to change, hit the RIGHT button.  The clock will freeze and you can keep pressing the right button to increment the digit to the correct value.  Wait for a few seconds and the clock will resume.  Repeat this for each digit.  You do not set the hour as "12" - you set the first digit to 1 and the second digit to 2.  The clock is in 24h mode so keep that in mind when setting it after lunch.

The clock is powered via USB.  There is a mini-USB (NOT Micro) on the left side of the unit.  I really appreciate the fact that this device does not use a wall adapter.  As any gadget lover knows, there are never enough outlets around.  By using USB, you can simply plug it in to your computer or any USB wall charger if you want.  The extra flexibility that this creates is great.  For example, I have my device powered by the USB out on my Epoch Clock and it seems to work fine.  Thankfully, this device includes a battery backup - the big black circle on the back of the unit.  This should prevent you from having to reset the clock every time the power goes out.

I haven't had the clock long enough to measure drift.  I don't intend to do formal measurements of this.

SZ-8 Nixie Clock


The tube itself is somewhat unusual.  It is an SZ-8 which appears to be a clone of a Z560M tube.  The letters are surprisingly "fat" but easily readable.  The tubes are not new but they do not show any obvious signs of use.  There is no evidence of cathode poisoning and don't appear to be any defects in the tube.  Additionally, the seller included a spare tube in case the original one breaks/dies/etc.  I do unsure if these tubes contain mercury.  They don't have the typical blue/violet glow like an IN-18 does so I am inclined to say they they do not.  (Mercury helps prolong the lifespan of the tube.)

SZ-8 Nixie Clock

The clock is smaller than an average smart phone. It is about four inches tall by two inches wide.  It is about an inch and a half deep, largely because of the tube.  There are four standoffs that are included which would help with mounting if you want to build a custom frame.  It does not, however, come with an enclosure.  This is my single biggest complaint about the device.  You probably won't be harmed if you touch the power supply but you might feed a bit of a shock.  I haven't tried so I can't say for sure, but 180v would probably be noticeable.  There is very little current so I highly doubt it would be anything more than a tingle.  The other problem that the lack of a case produces is that the clock doesn't want to stand vertically on its own.  It is top heavy because of the tube and the USB cord on the left means that it is constantly falling over. I have mine wedged on my desk to prevent it from falling, but an enclosure or sturdy base would solve this.

Overall I really like this device. When he produces more, go buy one.  At this price, you can't go wrong.  All of my complaints are minor and I doubt you could even build one of these clocks for cheaper.  I had a positive experience buying from Turbo_Hobby and would not hesitate to buy from him again.

UPDATE: 6-16-2010:

He now includes an acrylic enclosure with the clock.  This seems to resolve all of the stability problems I encountered.  Go buy it now!

Verdict: Buy It


  • USB Powered
  • Clean PCB layout
  • Battery Backup
  • Inexpensive
  • Well built
  • Unusual display


  • Top heavy design means it falls over frequently


by Patrick Mignot

Price: Not For Sale

I originally contacted Patrick about featuring his F9020AA Single tube clock clock on this site.  He has quite a few different devices that he has built and I wanted to share his #7 clock.  It is a single digit clock based off of an IN-4 ИН-4 nixie tube.  Of course, the stand out feature of this device is the shape of it.  Unlike something the Turbo_Hobby clock, this one also features a calendar and alarms/chimes.  Patrick also points out that the exercise of learning to read the clock provides a god source of mental stimulation.  While a single digit clock is not particularly hard to read, this does take a little bit of time to get used to.


Patrick Mignot #7 Nixie Clock

Images, video and description below are owned by Patrick Mignot and used with permission.

About This Clock

  • This is a single digit Nixie tube clock, will display one after one HH then MM
  • Originally fitted with a Russian IN-4 Nixie tube, any front view Nixie tube of the same diameter can be attached to this design, individual pin receptacles are used in place of a socket to plug the tube.(for transportation purpose, the original tube supplied with the clock is slightly silicon glued to the case)
  • The case is made of Cherry wood, varnish finish, no special care needed.
  • Tube backlight can be turned off (switch located in the case)
  • Feature smart single button settings and PWM dimming 0 to 100%.
  • High accuracy from a 4Mhz quality crystal
  • Power outage backup facility (no battery needed)



  • This clock is from an original design by my friend Rhett Bryson – Department of Theatre Arts – Furman University  - (SC - USA)
  • The clock has been made in France using high quality French Cherry wood (meurisier)



by Patrick Mignot

Price: Not For Sale

I know it is easy to impress me with unusual clocks, but this one really stands out.  I found this clock through an eBay auction for a very unusual F9020AA Nixie Tube.  Not only is this tube huge (it is nearly as tall as a B-7971), it is also flat.  I have never seen any other nixie tube with this design and I am having trouble finding more information on the tube itself.  (As an interesting note, six tubes like this was posted 1/24/2010 and it sold within 24 hours for $550 each.)

The dimensions are: (Height: 133mm (including nipple and pins) - width: 63mm - thickness: 34mm - digit height: 60mm - digit width: 40mm)


F9020AA Nixie Tube Clock

F9020AA Nixie Clock

(images used with permission)

Patrick has several other clocks that are worth checking out.  He provides plenty of photos of his work and even has a few numitron clocks and a B-7971 clock as well.



by Turbo_Hobby

Price: 35 SGD ~ $25 USD / eBay buy-in-now

UPDATE: Read the full review here

I just found a great little one-digit nixie clock on eBay.  The designer did a great job of fitting the timing circuitry, the power supply and display driver on a business card size PCB.  The majority of the components appear to be surface mount so you could easily repackage this in a more polished display.   For $35, this is also probably the cheapest nixie clock you can buy.


Single Tube Nixie Clock

The clock itself works like most single digit Nixie clocks.  There are four LEDs across the bottom representing HHMM.  When the first light flashes, the tens digit of the hours is shown, then the units position of hours, then tens digit of minutes, and finally the units digit for minutes.

One other notable attribute to this clock is the fact that it is USB powered.  For most clocks this isn't practical as the current is limited to 500mA on USB but it is more than sufficient for something this size.  The designer did a great job integrating the power supply on the board and even managed to add a battery backup.  It appears to be a mini-USB connector but I need to verify this with the seller.

No information is given about the time keeping mechanism.

The tube is an "SZ-8(QS30)" according to the YouTube Channel.

There are two downsides that I can see to this auction.  First, the seller has 0 feedback.  I am bidding on one right now (as opposed to buy it now) and I'll report how it goes shortly.  Second, the clock doesn't come with any enclosure.  It is highly unlikely that you will be seriously harmed touching this in operation, but picking up this clock while in operation might give you a bit of a shock.  Additionally, if it comes in contact with any metal objects while in operation, it may damage the device.  This is true for all exposed PCB clocks, but it is worth pointing out.

All of the images and videos are provided by the seller and used with his permission.

If it is half as good as it looks, the seller should raise the price by 100%.


From the auction:

  • 16mm digit, bright even in daytime
  • 4 LEDs indicating digit position, can be easily turned off
  • Powered by USB port, with backup battery
  • 24 hour mode
  • Two buttons only (one for LEDs, one for setting the time)
  • Made by high quality components


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