[MQ Matching Set of 4]

All Svetlana Vacuum Tubes were S logo and are produced in Svetlana factory under Dewu Svetlana JSC umbrella under Sanctuary and distributed by Svetlana Electron Devices (SED), which was a worldwide general agent.
The S Logo trademark was sold by the SED company in 2001 and was sold to New Sensor (NS) to manage debts. From this time, Svetlana JSC has switched to all vacuum tube logos produced in Svetlana factory to the KC Logo (Winged-C).
This S logo Svetlana vacuum tube is produced in NS Reflektor factory (same factory as SOVTEK, Electro-Harmonix brand) in Saratov, and is sold by NS logo Svetlana.
The Svetlana (S Logo) vacuum tubing is available here to be given a 13 digit serial number after adequately aging in domestic automatic sorting machines before being measured. (The serial number is attached to the box) Measured and matched and shipped. The error of the pair measured by NS company is often reduced by about dozens of percent even when tested in the same measurement conditions. However, with this high precision selection, the error of the pair can be reduced to 5% (depending on the measurement conditions).
Other than the electrical characteristics of the product (damage to other devices, bulb tilt, valve height, logo missing, etc.) are not covered under the warranty.