Audio Tubes Direct is an Authorized Tung-Sol, Electro-Harmonix, Genalex, Mullard, Sovtek & Svetlana Dealer. If you do not see the amp set you are looking for, please let us know. The Tung-Sol legacy continues with the 6L6GCSTR. The ultimate in musical tone and smooth overdrive, the STR delivers the sound that established Tung-Sol as the benchmark of quality. Built to the same “Special Tube Request” specs of leading amplifier manufacturers of the 1960s, the 6L6GCSTR is a rugged and reliable power tube for use in the most demanding guitar ampli?er circuits.The Tung-Sol 12AX7 is warm and musical with high gain, ultra-low microphonics and superb linearity with a dynamic 3-D sound. Manufactured in the famous Reflektor plant in Saratov, Russia, these brand new tubes have been tested on the industry's most reliable, voltage controlled testing equipment and exceed all manufacturer's specifications. They are guaranteed from the manufacturer to be new and free from any defects in materials or craftsmanship and are backed by our 30 Day Warranty. For sets that include a balanced preamp tube, the balanced tube will be marked with a yellow "balanced triodes" sticker. 10% restocking fee may apply.