Sovtek is a brand of vacuum tube owned by Mike Matthews's New Sensor Corporation and manufactured in Saratov, Russia. They are often used in guitar amplification and include the popular variants of the 12AX7, EL84, EL34, and 6L6 models. Many amplifiers in modern production come with Sovtek valves, due to their low noise performance and low prices.

In the 1990s, Sovtek also manufactured tube amplifiers which were manufactured in Russia and given names like Mig 50, Mig 60, Mig 100 etc. They were known for their high quality sound, good reliability and low cost. Today they are becoming somewhat collectible since they are no longer manufactured. New Sensor also manufactured speaker cabinets to go along with the amps(also Sovtek branded)that were fitted with US made Eminence speakers. At the same time, Sovtek also manufactured Russian variants of several effects pedals already manufactured in New York City, USA by Electro-Harmonix, another company owned by Mike Matthews. Sovtek released versions of the Electro-Harmonix Big Muff Pi and Small Stone pedals. Today, these pedals, along with the Bass Balls pedal, continue to be manufactured in both NYC and Russia, but only under the Electro-Harmonix name.

At this time Sovtek is used only as a nameplate for vacuum tubes manufactured by the New Sensor Corporation.

New Sensor makes tubes under many different brand names, Sovtek and Electro-Harmonix being only two. They recently acquired the rights to market tubes under the names Mullard and Tung-Sol. They also acquired the rights to the name Svetlana for North America out from under a competing tube manufacturer who now go by SED or "Winged C" in that market. New Sensor is currently making tubes under all those brand names.