eBay: Magic Eye Winker
Magic Eye Winker EAM86 6GX8
via eBay/ $98 / sold by Tortugascuba
I found one more magic eye winker in addition to the one yesterday. This one is a little more expensive but it comes as a complete kit. I really like this little version. There are no integrated circuits and it looks well built. I don't know if I would spend $100 on it..but I do like it. Check out the video and the description after the jump.
Magic Eye Winker. Similar to Dekatron Spinner. Uses a Valvo EAM86 (6GX8) Tuning Indicator Tube (aka Magic Eye).
Tuning indicator tubes, more commonly known as "Magic Eyes", found their place in early radios around the late 1930s. They were usually the more expensive radios, that used this feature, to aid in fine tuning of a radio station. By the early 1950s these tubes also were used as VU meters in early tape recorders. The EAM86 was specifically intended for VU meter service. They also found applications in many pieces of tube era test equipment, since they made such a handy unscaled meters. They were used in some fashion or another until the mid 1970s.
Magic eye tubes are simple voltage level indicators. Here are a couple of sites were you can see the various types made: Ake Holms Tubes and magiceyetubes.com. These tubes came with a wide variety of features, including multiple indicators, and with (or without) internal amplifying triodes. Some could be viewed at the top end of the tube while others were viewed from the side.
What I'm selling here is what I call a "Magic Eye Winker". Its a simple 'all-tube' circuit. NO Semiconductors: Transistors, IC, or Diodes.The eye winks open and closed due to the oscillation of its internal triode. That triode is wired as a phase-shift oscillator with a frequency in the ballpark of 1Hz (roughly one cycle per second). The 'rectifier' for making the 150VDC, from household 120VAC, is a common 6AL5 vacuum tube dual diode. The 6AL5 was more commonly used in radio receiver demodulator circuits. The 'eye' in this winker is an EAM86 (European designation), which is also a 6GX8 (North American designation). A "Winker" is to a Magic Eye, as a "Spinner" is to a Dekatron.
Here is a video at Dailymotion showing this unit working: Winker Video.
Here are some higher resolution photos: Top View and Bottom View. And here is an additional photo of The Rear showing the Siemens tube, though the unit being sold has a Valvo tube. The tubes are NOS.
The winker is housed on two clear acrylic plates. The top plate serves as the circuit board, with all the components mounted to it as if it were a PCB (printed circuit board). The bottom plate serves as the base, and keeps your fingers from accidentally coming in contact with the live (and hot) circuit. It also has the schematic engraved onto it. The tube sockets are actually individually socket pins which are suppose to be soldered to PCB pads. Here they are mounted in acrylic, without any pads, so they float a bit which actually reduces strain on the glass tubes (in pre-manufactured sockets, the pins float, which also cause no strain on the tube). This a completed unit, ready to plug in and go. It is NOT a kit, nor made from a kit. I designed and made it myself from scratch.
WARNING: This circuit plugs directly into a 120VAC household outlet, and is NOT electrically isolated. It should be safe to handle as long as you use some common sense. Keep it away from wet areas, such as near the kitchen sink, or a bathroom. Its not a good idea to have it on a shelf over your bathtub. The filament current is also taped directly from the 120VAC, and is limited to 300mA, due to the 6.8uf capacitor. That cap has a reactance of 390 ohms at 60Hz. At 50Hz the reactance would be 470 ohms, so the current would be limited to 255mA. If used in Europe, a 220V to 120V step down transformer is needed. Its 'All-Tube' so static electricity is not a problem. It should even withstand an EMP.
eBay Seller: Tortugascuba