Matched Pair Vintage General Electric 7581A, Tested Amplitrex. Tube are a close match at 6100 and 5850. Tubes are the same construction with double side getters, Getter flash on 6100 tube has a small dark spot.The 7591 is the heavy duty, better construction, 6L6GC. Will substitute in place of KT66. One does not have to be an expert to recognize the high build quality. Even the glass seems thicker.
Production codes 63-09 & 63-C9 with the code 188-21 indicate GE manufacture. You can expect to hear a sound quality difference when substituted for 6L6GC. Please have an experienced vacuum tube technician install the tube and set bias.
IMPORTANT - Be sure to read the Terms and Conditions of Sale. Hardware Packing - Domestic and Outside US: Item will be wrapped with bubble wrap in two directions and double boxed. Use of a friend's account or biding for a friend is not allowed.The item "Matched Pair Vintage General Electric 7581A, Tested Amplitrex" is in sale since Sunday, April 12, 2020. This item is in the category "Consumer Electronics\Vintage Electronics\Vintage Audio & Video\Vintage Parts & Accessories\Vintage Tubes & Tube Sockets". The seller is "wevtt" and is located in Waltham, Massachusetts. This item can be shipped to United States.