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Only the very best for the Queen !

The "NumiQueen" is a tube clock kit designed around six Russian IV-13 Numitrons. In our opinion, these are the finest numerical tubes ever produced in the 80’s. There is a good reason why the IV-13 is called the Queen of the Numitrons. With its extra large 22mm high digits and a warm orange glow, it is very pleasing to look at and can be seen from a fair distance. Coupled with modern control circuitry, we developed this very unique tube clock kit, the first of its kind using 6 x IV-13 Numitrons.

So what are Numitron tubes ?

A Numitron utilizes eight filaments for the display, seven for the segments, and one for the decimal point, all of which are enclosed in a typical tube glass body. In effect, a Numitron can be seen as an eight-way incandescent globe.
The big advantage of using a Numitron as compared to the more popular Nixie tube is that the Numitron only requires very low control voltages of 5VDC as opposed to about 170VDC for the typical Nixie tube or around 5 VAC and more than 20 VDC for the well known green / bluish VFD displays. Because of these lower voltages a Numitron, such as the smaller IV-9, can be directly driven from the control counter circuits. For this reason there are already a number of Numitron clocks available on Ebay using this smaller IV-9 Numitron.
However using the much larger IV-13 Numitron requires a more complex and powerful driver circuit as each of the eight segments of the IV-13 draws about 32mA of current! Another challenge in driving Numitrons is that they does not lend itself to be easily driven by a conventional Multiplex circuit.

Mr. Nixie’s unique solution and design

The answer to the challenge of controlling the IV-13 Numitron is the Texas Instrument TLC5916 Constant Current LED Sink Driver chip! Using the TLC5916 also gives us some unique and very desirable features:

  • Due to the constant current source, each segment of the IV-13 does not suffer from the usual ‘cold start’ inrush current experienced by the filaments.
  • This drastically extends the lifespan of each filament/segment in the IV-13 to much more than 50,000 hrs. Because of the harsh inrush current, e.g. an incandescent bulb usually always fails when switched on.
  • Each filament/segment of the IV-13 will glow at a constant and identical intensity. Tests have shown that if a conventional control circuit (constant voltage) drives the segments of the IV-13 there can be a variation of up to 20% of the current consumption and therefore brightness of each segment, which would be very noticeable and undesirable in a digital clock if two or more of such different tubes are fitted. By using the TLC5916, each segment of the IV-13 will get its "own" 32mA current irrespective of the voltage level with the result being that each segment glows at an identical intensity.
  • One of the drawbacks in using a constant current source is that the reaction time of each segment to come up to its full glow is rather slow. For that reason, once again, we came up with a very unique feature. Each filament/segment is constantly ‘pre-heated’, which results in a very quick reaction time for the relevant segment to turn on when required.


  • Hours, Minutes and Seconds display without Multiplex
  • Selectable 12 or 24 hour display modes
  • Uses a Quartz Crystal Oscillator as timebase with software adjustable accuracy
  • Programmable leading zero blanking
  • Date display in either DD.MM.YY or MM.DD.YY or YY.MM.DD format
  • Programmable date display each minute or selectable with a single button push
  • Alarm with programmable snooze period
  • Optional DCF / WWVB / MSF / GPS / NWTS sync. with status LED; prepared for fitting the ASK receiver module from the „Wireless GPS Set 3“
  • Dedicated DST button for easy switching between DST and standard time
  • Super Capacitor backup keeps time during power outages for more than 6 hours.
  • Simple time setting using two buttons
  • Column settings (Flashing AM/PM indication, illuminated AM/PM indication, always flashing, always on / always off)
  • Seconds can be reset to zero to precisely set the time
  • Programmable night mode - half brightness or blanked display to save tubes life or prevent sleep disturbance
  • Weekday aware „Master Blank“ function to turn off all displays on weekends or working hours
  • Separate modes for column LEDs during night mode
  • Standard or fading display modes as an eye-catcher
  • Standard date display of shift in / out effect with scrolling digits
  • Tubes lighting with LED colours at your choise incl. RGB auto changing colour
  • LED brightness adjustable for every hour
  • Programmable temperature display in °C or °F at seconds 30...35
  • All user preferences stored in non-volatile memory
  • No SMT design, only through hole components
  • Tube sockets for easy replacement
  • Constant current drive for drastically extended lifespan (much more than 50,000 hrs)
  • Selectable filament pre heating for faster reaction time of the segments
  • 7.5 VDC desktop power supply incl. mains cord is included

What you'll need:

  • 3 hour of your evening time with no hurry
  • A clear, well-lit area in which to work
  • Soldering station and fine electronic solder
  • Multimeter to check the generated voltages
  • Electronic tools
  • A loupe may be helpful
  • TX10 (Torx) and PH1 screwdriver
  • Download of the manual
  • Enjoyment of your work of course
  • 6 x IV-13 tubes (offered separately)

RFT receivers

NTP receiver
The modern art of time keeping:
Via Internet and a domestic Wi-Fi the time data will be received from a "timeserver-pool", converted into a pseudo GPS format and interpreted by the clock.
  • Easy placement
  • The NTP must be able to connect to a 2,4 GHz Wi-Fi network
  • Only onetime configuration through Laptop / Tab or Mobile Phone with the web browser
  • No software or App installation necessary
  • World time (UTC) is transmitted, which means that the clocks have to be configured once for the corresponding time zone and need to be set between DST and Non-DST twice a year by pressing a button
  • Can be used worldwide


DCF receiver
The proven time keeping method in Germany and neighboring European countries:
From radio station "DCF-77" in Frankfurt/Main, the time signal is continuously transmitted and received within a radius of about 1,000 km. The external DCF receiver forwards the signal to the clock for synchronization.
  • Orientation to the radio station in Mainflingen near Frankfurt is necessary
  • Unfortunately interference-prone 77.5 kHz long-wave transmission, therefore reliable synchronization only at night hours
  • During synchronization the Nixie tubes should be switched off (can be set-up in the options menu of the clocks)
  • Central European Time (CET) is transmitted with automatic switching between DST and Non-DST
  • Can be used in Germany and the neighboring European countries


Wireless GPS
The wireless way of time keeping, specially with multiple clocks:
The data sent by the GPS satellite system is received (similar to the car's navigation system) and converted into a 433 MHz signal, then transmitted intermittently and received from an internal fitted ASK module.
  • Placement the Wireless transmitter on a window frame with a clear view to the horizont is required
  • Wall outlet for powering the Wireless transmitter necessary
  • 433 MHz signal strenght up to 20 m indoor
  • Every clock must be equipped with an internal ASK module
  • One Wireless transmitter can be received by any number of clocks
  • World time (UTC) is transmitted, which means that the clocks have to be configured once for the corresponding time zone and need to be set between DST and Non-DST twice a year by pressing a button
  • Can be used worldwide, but specially intended for Export, therefore the manual is only available in english speech
These wireless components consist of the following devices
1.: A wireless GPS receiver with USB power supply for placement on a window frame.
2.: An ASK module for fitting into the clock.

If you want to use Wireless GPS synchronization for the first time, we recommend to order a Wireless Set 3 as all necessary components are already included. Later, to expand to every new clock, you only need an internal ASK module.


Look at RFT Receivers


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Complete electronic kit incl enclosure and Power Supply

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The prices of the DE / EU versions includes the German VAT.
Handling fees
Higher handling costs for export are already included in the item price exept of import duties, taxes etc. These charges are the buyer's responsibility.