I haven't owned all that many Visseaux tubes but every one I had looked to me like a re-branded or OEM'd RCA tube. And Popes were a Philips brand, made in Holland.
A Tube Change Really Can Make A Difference
So, I have been using Visseaux 6V6GTs in my BAT VK-3i preamp for years. Changed them out for a pair of Pope 6V6GTs and, whoa ... what a palpably sonic difference! The Popes have much greater midrange energy than the Visseaux, throw a wider soundstage, and have much more air around voices and instruments, particularly on the top end. I can describe it only as "sparkle" ... decay is greater, too. The Visseaux sounds quite a bit softer/more cushiony than the Popes. I never thought that there could be such a huge difference in sound from a 6V6 tube, but there ya have it.