From The Tube Stores review, "When driven into distortion it starts off a bit crunchy like a 6L6 but as you push it, the sound blooms into that singing EL34 tone with great sustain and modest compression." From the manufacturer: "The Tungsol EL34-B is a higher impedance EL34 tube design with increased touch responsiveness and a unique clipping characteristic with a hint of the 6L6 sound."
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.