The Tung-Sol name and trademark have been acquired by the New Sensor Corporation. This new production Tungsol tube is manufactured at their Xpo-Pul factory (also known as Reflektor) in Saratov, Russia. New Sensor is an American corporation and since taking ownership of this factory has been steadily improving the quality of current production tubes.From our review of this tube: "There are only so many ways to describe tube tone and most have become cliches. The Tung Sol 12AX7 has the gain and drive of a Chinese 12AX7 and the pure tone of a Mullard or Brimar."According to the manufacturer, this Tungsol 12AX7 is the Ultimate 12AX7. Big, warm, and musical. High Gain, ultra-low microphonics, and superb linearity with a dynamic 3-D sound.One other note about the construction of these audio tubes is they have filaments that are almost completely encased in the plate structure. They don't "light up" brightly when working