Can you remember grandma's old tube radio with the "magic green thing" in the front which showed the quality of the signal reception?
If you're looking on Ebay for "Magic Eye" than you'll find not only a lot of tubes but also offers of VU meter kits. But as against the most Ebay offers you need not to supply all the voltages (normally 6 V and 250 V), you do not need to build a case, solder adapter wires for the tube's connections, have only a mono display or only one tube type which can be fitted.
Mr. Nixie has taken all these kits, put them in a pot, added a hefty dose of the legendary Mr. Nixie Magic, and finally the Universal Magic Eye VU-Meter was created.
You can fit into this VU-Meter the most commonly available Magic Eye tubes without the need to do any soldering. Even the different filament voltages doesn't matter as they can easily be set with a DIP switch for 4 V / 6 V / 12 V and 19 V.
Built in to the circuitry is an automatic level control, therefore your Magic Eye will always display a signal, regardless of the input level.
Another highlight is the true stereo design of the circuit. By inserting e.g. the EM83 stereo Magic Eye tube, you'll get a real stereo dual display with only one tube.
Also three different stereo boards are available for stereo display with two tubes each.
See here some examples which tubes can be fitted on the black tube board:
Front: UM85, EM83, 6E1P / Rear: EM84 / EM800
You do not need a solder iron to swap the tube's type on the black tube board. A simple Torx screwdriver is enough.
Thanks to different coloured stereo tube boards even two Magic Eye tubes can perform a stereo display:
Blue board: 2 x EM80 / 6E1-P / EM81 or 2 x EM84 / 6E3-P / EM87 / 6E2 / EM800
White board: 2 x UM80 / UM81 or 2 x EAM86
Yellow board: 1 x 6C5 / 1629 or 2 x HM 85 / UM85
Green board: 1 x EM71 or 1 x EAM86