The converter allows you to place ZIN18 tube with non-standard pins, in the original IN18 tube socket. ZIN18 tubes are produced in two pin versions. One version has standard pins the same as IN18, while the other version has non-standard pins. The converter is dedicated to tubes with pins not compatible with IN18.
The project is based on two PCBs connected via 4 pin header connectors. The diameter of the PCBs is 30 mm (1.18″).