So I'm looking retube my recto and was wanting a little expertise from some of you knowledgeable tubers.
In my amp, i'v been running Russian 6l6's and chinese 12ax7's groove tubes. I' been happy with the sound, but the pre's are used from when I bought It a few years ago.

My question is, are Russian tubes vastly better to Chinese tubes? Would I notice a difference If I sprung for the Russian pres? I' tried sovteks and Mesa pres in there and didn't care for them.