|Tung-Sol 6AL7 Magic Eye Tube
|Written by AnubisTTP on 2017-02-23
Not all top view magic eye tubes have a circular target. The 6AL7, manufactured by Tung-Sol as well as other companies, is a tuning eye tube with an unusual triple-bar pattern. Each bar in the 6AL7's display pattern is split in half; the bottom of each bar can be controlled separately, while the top section of both bars are ganged together into a single unit. This allows the tube to display up to three linear measurements simultaneously. The 6AL7 is a fairly common part, but its lack of an internal triode complicates the process of adapting this tube model to replace rarer tuning eyes. Builders must typically add an external triode or semiconductor stand-in to adapt this display into devices not designed to use it.
General Electric 6AL7 Datasheet (PDF)
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6AL7 tuning eye tube, normal operation.
The 6AL7 magic eye tube, underside of phosphor target.
6AL7 pinouts and basing diagram.