I am visiting this page as a result of the selection of comparisons that are referring to the E 6SN7 being a comparable match to the KR 6SN7.
I have tube rolled the 6SN7 as a input tube on a 845 Mono Block Power Amp, out of three vintage tubes, four modern tubes and a 68HC the Black Glass KR was very attractive and the preferred tube.
The E6SN7 is on my radar as a result of favourable comparisons being reported on to the KR Tube.
The earlier reference to 845 Tubes has been well received.