Nixie-based tube clocks

Recently, Pete launched his new Nixie QTC format for mid sized tubes. Let's take a look at what he's got:

To begin, QTC stands for "quick tube change." The QTC design is an interesting clock kit with the ability to easily replace tubes that previously were hard wired (such as an IN-8-2, Z5070M, or ZM1210). He does this by putting them on a mini PCB with a connector on the back so the tubes can easily be swapped out. Nixie tubes do eventually wear out and this is an elegant way to replace them. One of the advantages of having all of the tubes on mini PCBs is that the main board can support multiple types of tubes with no configuration.

The nixies are drive in a multiplexed display mode. The tubes are driven in a 3x2 multiplex and generate little noise and no perceivable flicker.

This device also supports GPS synchronization making it one of the most affordable clocks with this option.

The following features are standard for the kit version:

  • 6 X (your choice) Nixie tubes, with 18mm digit height
  • 6 X Tube cell components for mounting the tubes
  • All transistors, resistors, capacitors, ICs, diodes
  • 2 X Neon bulbs for hours:minutes:seconds separators
  • Double sided, plated - through - hole PCB with red solder resist.
  • Fully pre-programmed PIC microcontroller, with socket
  • Piezo alarm sounder
  • RGB LED Tube Lighting Pack

Kit with IN-8-2 Tubes:


With IN-14 Tubes:

Aluminum case:


Other Features:

  • Hours, Minutes and Seconds display
  • 12 or 24 hour modes
  • Uses a Quartz Crystal Oscillator as the timebase
  • Programmable leading zero blanking
  • Date display in either DD.MM.YY or MM.DD.YY format
  • Programmable date display each minute
  • Scrolling display of date or standard display
  • Alarm, with programmable snooze period
  • Optional DCF / WWVB / MSF / GPS synchronisation with status indicator LED
  • Dedicated DST button to switch between DST and standard time
  • Supercapacitor backup. Keeps time during short power outages
  • Simple time setting using two buttons
  • Programmable leading zero blanking
  • Five programmable neon colon settings (Flashing AM/PM indication, illuminated AM/PM indication, both flashing, both on, both off)
  • Seconds can be reset to zero to precisely the set time
  • Programmable night mode - blanked or dimmed display to save tubes or prevent sleep disturbance
  • Rear Indicator LEDs dim at night to prevent sleep disturbance
  • Weekday aware ‘Master Blank’ function to turn off HV/ tubes on weekends or during working hours
  • Separate modes for colon neons during night mode
  • Standard, fading, or fading + scrollback display modes
  • ‘Slot Machine’ cathode poisoning prevention routine
  • Programmable RGB tube lighting – select YOUR favourite colour palette
  • 729 colours possible. Have a different colour of your choice every hour, or autochanging colours
  • Not AC frequency dependent – works in all countries
  • All user preferences stored to non-volatile memory

"Lars" and "Laura" are two old school Nixie Clocks from At the time of writing, Laura is no more, but "Lars" (the little clock on top of the larger one) is still available. seems to have lost the drive to make new clocks, or even replenish stocks of the old ones, and it appears that as the old models run out of stock they are not re-ordered.

In any case, "Lars" is still available, and has 6 x IN-17 tubes. This video shows some of the display effects in action. 

The display effects are the same as the ones that Pete Virica uses in his QTC clocks. The PIC micro controller software was designed by him and modified Jürgen for these clocks. The lack of updates to this firmware might be a sign that nothing new is coming out of this collaboration.



See more at




Here is a new clock coming soon from - this is Laura:

Laura Nixie Clock

An IN-2 clock, based on the features from Sven - incl. Alarm, but with some more improvements:

  • High quality socket pins for the socketed IN-2
  • 2 x 3 multiplex for higher brightness / less tube noise
  • High Efficiency HV voltage converter "ultra cool design", therefore the clock can be easily powered from a single USB connector (power consumption less than 2 VA incl. turned on LEDs) and all electrical parts (incl. MosFet and inductor remains cool - not even warm).
  • As an option: Build in ASK receiver module for "wireless GPS reception"
  • External connector (1/8" TRS jack) for DCF/MSF/WWVB or wired GPS receiver (BR-355)
  • Easy enabling or disabling Day Saving Time by a single button's push
  • RGB controller for tube backlight with selectable LED fixed colour / brightness for every hour and / or auto changing colours with variable speed
  • Extra master blanking time for disabling the complete display during weekdays / weekends etc.
  • 1F Super Cap power backup for keeping the time for more than 24 hrs without power supply
  • New extra optical Nixie effects: fading digit with "scroll back", date scrolling in and out

Laura Nixie Clock

Laura Nixie Clock


LEDs on rear for: Alarm, DST active, Time Sync, Time Data input

The PCBs are made with a lot of tiny SMT parts, but they are all pre-assembled and soldered. So building the clock within 2 hrs. is not a problem at all.



Here is a great clock from Michael B. This is the RackMountable Nixie clock. The enclosure was purchased off of eBay, polished up, and brought back to life with the electronics from a NixiChron. Take a look:


Rack Mount Nixie Clock Rack Mount Nixie Clock Rack Mount Nixie Clock

Rack Mount Nixie Clock


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