I'm happy with this. Better than JJ's !
I have a 1996 USA made, Fender Roc-Pro 700 combo, which is a SS / Tube hybrid which I acquired late last year. Even though it had the original stock Fender 12AX7 and was still running fine, I felt after almost 20 years, it was time for a tube change. Now I know that Groove Tubes has a great rep and seeing that they're owned by Fender , I figured I had nothing to lose, so I decided to give the 12AX7 R3 a shot and I'm glad that I did. This preamp tube has breathed new life into my Roc-Pro like you would not believe. It did take a couple of days to get warmed up but once it did , I could not believe the difference. There is a major increase in volume on both channels. The clean is more refined and not as trebly while the Gain has dare I say it , more balls, to it ! If this tube can last at least a year or two, then I'm sticking with this one.