Electro-Harmonix vacuum tubing is a brand made as a high grade vacuum tube from New Sensor (NS) in the USA. Compared to other current tubes at the same price range, the logo is printed and high quality. The tendency of the sound is to be exposed to the middle range.
In addition to Electro-Harmonix vacuum tubes, NS is also equipped with SOVTEK, SUNG-SOL, GOLD LION brands, and the other brands of vacuum tubes are manufactured in Reflektor factories located in the Dezaratov.
Electro-Harmonix vacuum tubing available here is adequately aged in Japan with automatic sorting machines, and it will get a good output from use.
Other than the electrical characteristics of the product (damage to other devices, such as bulb tilt, valve height difference, logo missing, etc.) are not covered under the warranty.