MINIWATT tube amplifier

Regulating multigrid heptode (seven-electrode) tube amplifier. This piece is particularly interesting because a stamp has been wrapped around it—this is a customs revenue stamp for Perfumery-Distribution and bears the emblem of the Franco Regime, dated May 1969. The stamp is evidence that the item was imported on this date, likely from the Netherlands, where the manufacturing company Miniwatt (a subsidiary of Philips) was located.

Thermionic valves or electric tubes are devices installed to regulate the electric current. They are designed to create an internal electric current (based on the physical property of thermionic emission, also known as the Edison effect or Richardson effect). They can amplify, switch, or change an electric signal and were the basis for creating the first electronic devices, such as radios, televisions, and computers. This piece may have been part of some laboratory equipment used in physics experiments, or it may have been a replacement part for a radio or some other electronic device in a school.