The "ITS1-A/B Thryratron Nixie Clock” by Jürgen Grau


H More on the ITS1A Thyratron tube:

The ITS1A display tube is a bit of a mystery since it is poorly documented and little is known about  the application for the tube. It was manufactured by the Soviet Union at the height of the Cold War when LEDs and VFDs were readily available. But, why then was it developed?  It may be these tubes were developed for SW radio applications since their internal ‘multiplexing ‘ capability yields little or no EMV to interfere with weak signal reception. OR, unlike nearly every other neon display, which require control signals in the hundreds of volts range to activate, the ITS1A can be connected directly to a micro-controller and run with TTL level 5 volt signals. This is possible because the ITS1A contains seven tiny thyratrons, one for each segment, which perform the level shifting to control the 300 volt signals needed to ionize the gas inside the tube. The ITS1A is also unique in that it is a neon tube that does not glow amber like all other cold Cathode tubes, instead each of the tubes display segments is a phosphor-coated cup that illuminates green by electron spatter from the control thyratrons. In operation and when viewed from the side this beautiful little tube actually presents in three colors; pink/purple from the neon ionization, a little bit of blue from the electron paths inside the thyratrons, and from the front, the segments glow a beautiful cyan/green from the phosphor coating.

Michael Barile LLC

A beautiful clock for a beautiful little tube!!

The ITS1A clock by Jurgen Grau is one of my favorites from this designer and most prolific manufacturer. To my knowledge this is the 1st production clock developed and mass produced using the ITS1A Thryratron tube.

The clock is sold as a kit with all the small SMD stuff done for you and only the through hole components left to install plus the construction of the case. The components are a breeze to install however, the tricky part is installing and aligning the tubes. Most of these tubes are very irregular in size and shape and therefore making sure the overhang and overall plumb of the tube is correct requires some finesse and takes time to get right. The tubes protrude from the case quite a bit  (which I think is neat) and the back of the tube envelope actually makes contact with the backlight LEDs, depending how far you choose to have them stick out.  Therefore, the tube with the longest envelope will determine how far out the other 5 tubes are set in the case and this tube should serve as your gauge. Once I figured this out as well as the best way to feed the tube wires (see pics) into the sockets it was smooth sailing.

The clock can be GPS disciplined using either a BR355/Haicom 204III or an internally mounted GPS option. Firmware is once again done by Pete Virica and works nicely and is virtually identical to the Jenny Reloaded . One feature of the 1st Jenny I miss is the color freeze feature that allowed the user to freeze any color of the backlit LED colors indefinitely. But even though the backlit LED’s are nice, I still prefer them off to appreciate the beauty of these little tubes.

I really like The Black, White and Clear acrylic color scheme of the case and think it compliments the colors of the tube perfectly. Case went together without a hitch and all parts fit nicely. One thing I should mention is the clock ships with Red Rocket colon LED’s.  I chose to substitute conventional green LED’s, the color of the tube segments, for these red colored LED’s. I believe Jurgen will now provide green Rockets upon request. Oh, and another thing I learned about the ITS1A is that it comes in 2 flavors, with purple face washers or with white. Both are beautiful, but I prefer the purple.

I liked this clock so much I bought 2 more! Yikes!!

Decided to add double colons to the 3rd clock I bought ...pretty pleased with the result