When manufacturers such as RCA, GE, Telefunken, AEG, and Phillips, batch tested new vacuum tubes 40 or 50 years ago, they published a nominal or average value for a category of tubes which described that tube's electrical performance and characteristics. This published value, listed in tube service manuals, is called a bogey value.
In manufacturers' specifications for electronic devices, a bogey device (or bogie device) - especially a vacuum tube- is one that has all characteristics equal to the published values, in other words that its parameters all lie in the centre of their bell curve distributions.
Back in the day when tubes were the main active devises in electronic equipment, and were in mass production, bogie tubes were actually manufactured with the intent of being a bogie, or standard tube. During the hay day of tube technology and manufacturing tube producers would make special production runs of specific tube types to be used as Bogie tubes for specific needs within the industry. They paid close attention to the total assembly process, quality control in the production operation and testing procedures. They allowed sufficient burn in times to insure a stable and accurate Gm value as well as for many other characteristics. This was to insure these tubes were as close to the nominal design target values as could be achieved at the time. Today few if any tubes are made to this standard of attention to detail.
Bogey Value Classified Tubes Purpose
Voltage Amplifers, Power /Current Amplifers, Beam Power Tubes, Converters, Mixers, Gated Amplifers, FM Detectors, AM Detector Diodes, Power Supply Rectifiers, Relay-Control, Damper Tubes, TV Deflection, Regulators, UHF Oscillators, HF Oscillators, Mixer-Oscillators, High Voltage Rectifiers, complex wave generators, voltage regulators. Other classified characteristics were Lo Mu, Medium Mu, High Mu, Sharp-Cutoff, Semiremote-cutoff, Remote-cutoff, Low power transmitting tubes and high power transmitting tubes and tubes for computers.
Modern Tubes
Modern tube makers focus primarily on producing enough output in their regular and mostly audio tube production to meet sales demand! Which quite typically has a wide range with regard to their Gm values from the nominal design target values.
Today some suppliers will use a service tester like a Hickok 539C or some other such make or model service tester and test a tube and then market this as a Bogie tube for its Gm value.