Audio Research SP-10 6922 or 6DJ8

Thanks to both of you for your advice. My SP-10 MK 2 posessed the most perfect midrange phono reproduction I had ever heard.....until my phono (4) tubes went. They were big bottle 6dj8s marked with no name, except "made in USSR" The sound was big, lush, 3D bigtime! and no brightness. The plates on these tubes were extra wide. Tried the ARC preferred Sovtek 6922 and was astonished at how bad the sound had become. The line section tubes were also a bigger bottle tube marked AMPEREX, made in Poland, Anyone ever seen an Amperex made in Poland? Also wonderful sound. The Telefunken ECC88 is wonderful, but somewhat hyper/detailed and missing the ultimate vocal warmth of the old tube

Thank you Albertporter for confirming my suspicion that the"naturalness" was in fact due to tube wear. All other tubes in my unit were not replaced.Has anyone been able to replicate the great sound of these NOS tubes. We read how the Chinese and Soviets have "EQUALLED" the sound, but it may be a case just like the Stradiarious violin. What do you think?