Groove Tubes GT-6CA7-GE vs NO GE and NOS Sylvania


Anybody heard the difference between authentic NOS General Electric 6CA7's and the Groove Tubes GT-6CA7-GE? And what about the NOS Sylvania 6CA7's...how would they compare?

Any input is most welcome
128x128infotrad
I've been using the NOS Groove Tubes for some time. Amazingly strong, clean and accurate. They don't sweeten or mellow the sound like some and appear to have pretty flat response. To me, these are worth as much as NOS Mullards and I like the sound better.
Elevick: Are all 6CA7 Groove Tubes NOS tubes? In other woors, would you recommend any Grove Tube 6CA7 (in good condition, of course)?
I would be careful. There have been reissues as well as many different years. My quad has been carefully matched and has the tech's codes on them. If you are really interested, email me and I'll send you a photo of mine for reference. I am 100% positive of the quality on mine.
emfoods@yahoo.com