Magic Eyes
These are mostly miniature Cathode Ray Tubes (CRT) with an electrode (or several) to vary the size of a shadow according to signal level. One Magic Eye works in a similar way to a VFD (Vacuum Florescent Display), the DM70 / DM71. The DM160 and the similar Russian iv15 are not Magic Eyes, just VFD type indicators.
Commonly available Magic Eye valves (Tubes)
Also search for: Magisches Auge on eBay “worldwide”. Also note German speakers “Röhrenradio” = “Vintage Radio”
6E1P, 6BR5, EM80
EM81
6E5S, 6E5G, 6G5G
EM84, 6FG6, 6E3P
EM87, 6E2
Read my article on The Radio Museum
Links
All about Magic Eyes (best site!)
Magic Eye Tubes by AKH (also good)
Wikipedia on Magic Eye Tube (overview)
FC’s Fluorescent Magic Eye tubes
BPCV site on Magic Eyes including connections
The National Valve Museum: EM87 and other exhibits. (Search the parts above)
The Radio Museum: EM87 and other exhibits. (Search the parts above)
How German Tuning Indicators work (Radio Museum)
History of Tuning Indicators (Radio Museum)
Museum of Technology Magic Eyes
Cyclops one Tube Radio
Tuning Indicators at Wumpus’s Old Time Radios. (lists 143 types!)
Replacing 6.3V Magic Eye with 12.6V “1629”
Electron Ray Tuning Indicator Tube aka Tuning Eye (Circuit of operation)
German Site of Magic Eye Roehren
Peak Program Meter using Magic Eye
Nixie and Magic Eye Tubes
Philco Service Hints 1938 article
Classic Wireless UK (specialises in Murphy Radio) Tuning Indicators
Capacitor & Resistor Tester Bridge and Leakage Meter (Greyhills CR50 on this site)