I thank you for the input. I am currently searching for nos 6l6 tubes. I will advise you of the results.
*** I would like to mention that I have run tube amplifiers since 1975. I Started with Audio Research D-51, went to a D-75, D-76, experimented with Dynaco stereo 70's, back to ARC D-76 and D-51. I loved the 76 but wound up selling the D-76 after the old stock tubes wore out. ***I replaced the worn tubes with Russian tubes and the sound was hard and metallic, similar to a solid state amp. The amplifier never sounded musical with Russian tubes. I replaced the Russian tubes with Tesla KT-88's and it sounded pretty good. I guess the old tube designs contain some hidden secrets, or it could be in what types of steel were used in the making. Whatever it is, it just hasen't been passed on to the new tube manufacturers. I will keep you posted.
*** I would like to mention that I have run tube amplifiers since 1975. I Started with Audio Research D-51, went to a D-75, D-76, experimented with Dynaco stereo 70's, back to ARC D-76 and D-51. I loved the 76 but wound up selling the D-76 after the old stock tubes wore out. ***I replaced the worn tubes with Russian tubes and the sound was hard and metallic, similar to a solid state amp. The amplifier never sounded musical with Russian tubes. I replaced the Russian tubes with Tesla KT-88's and it sounded pretty good. I guess the old tube designs contain some hidden secrets, or it could be in what types of steel were used in the making. Whatever it is, it just hasen't been passed on to the new tube manufacturers. I will keep you posted.