I've had my Vox VT40+ amp for a few weeks and it's a great amp. Sounded really good but then I need to look at the pups on my Parker PDF30 guitar because they sounded a bit too good for a $200 guitar. The manufacturer says it's made by Duncan but I don't buy it as it's not marked.
Anyway I always liked vintage tubes and my amp uses one 12ax7 tube in the power amp stage. It has a Sovtek 12ax7wa tube in it and they.re pretty solid tubes but not spectacular. I wrote to a tube dealer about the tubes on his site I'm interested in. He recommended the British Mullard 12ax7 branded as an RCA and at half price at $40 so I ordered it.
I got it yesterday and boy does it make a world of a difference. A creamy brown gravy comes to mind.
I'd guarantee that Buck would love to play this amp.
An update. I just learned from a tube vendor at another guitar forum that this pic I posted is an RFT (made in Germany) 12ax7 tube. Still a great tube but he said I probably paid too much for it. My tube vendor offered to refund $7 but I told him just give me store credit instead. He also corrected his ad.
Wow. I bet lots of tube shenanigans go on. I've never thought much about tube replacement or substitutions unless there was something obviously wrong with the amp sound. I know folks do it all the time.