Groove Tube EL34LS

Groove tubes are sounding great in both of my amps: a Marshall 50W combo and a Fender Vibrolux Reverb!

Find out who makes groove tubes. For some reason, I THINK they are made by JJ. A review I read somewhere that I can barely remember. I don't want to start false rumors, but check it out, in case they are the same thing.

i think that groove tubes uses different suppliers depending on what tube. Their claim to fame is going through the tubes and applying strict quality control and matching. You can order output tubes based on break up characteristics based on this matching...i.e. some 6550s or 6l6s will break up earlier than others so they batch the ones with similiar characteristics.

They also have a 12ax7 preamp tube that is supposed to closely match mullards at only twenty some dollars a wack. A lot cheaper than NOS if they are true to their advertisement/

I'll reignite this thread. How good are Groove Tubes. I', particularly interested in the EL34 XF2, but general observations and comments are also of interest.