Two versions of the Eital-McCullough 4W20,000A power tetrode: at left., an early version (1952), cut open to reveal the “bombardment” cathode; at right, one from 1955. This tube is documented extensively in TC for oct. 2010. A very early bulbedd model, possibly the X486 protype, is illustrated on Norm Wilson’s n6jv.com web site.
In this issue
- A Vacuum Tube Test Console for Semi-Conductor Curve Tracers.
- Progree in Electron Tube Reliability
- Low Temperature Glass Sealing
- “Special Red” Tubes
- Tubes for Automatic Assembly
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