Welcome to the forum and this thread, TS. Good to have you. We are looking for more tube tweakers to get involved.
The ICBM is a RCA/Mullard 12AX7 tube that I bought on Ebay that measures almost 150 per cent of a new tube. Hence the ICBM term as it will blow something up.
The BP is the Raytheon and it is almost as strong. It is a wonderful black plate.
I bought these two tubes, with shipping for $48.37. They both came in their original boxes and tested much higher than a NOS tube. I also just recently got six 12AX7 Mullards that all tested as new for $69 plus shipping on an Ebay transaction. So the bottom line is, you can get some attractive tubes at reasonable prices.
If you have read the posts, you know that every tube has its own sound/tone.
I'm sorry if you were led to believe otherwise. A 1959 RCA gray plate with ribs is going to sound different that a JJ. I sent Josh a gold pin JJ and in his tests it sort of became the hind tit on the boar hog. "It's okay, but it doesn't sound as good as a USA NOS. There are many different types of 12AX7 tubes. Some aren't available anywhere at this time. Some of the sub's for 12AX7's sound better, but to find them is a difficult task. 12DF7, 12DM7, 12DT7 and 12DW7 are all out of stock tubes that will sub for a 12AX7. Then you have your other High MU tubes such as a 7025 and a 5751. Also used is a 12AT7. All of these tubes were made by many different manufacturers. Just like there are many ways to bake chocolate chip cookies, there are many different ways to make a tube. The coatings on the plate, the length and thickness of the plates, the size and location of the getter(s) all can attribute to different tonal qualities.
I know that Eurotubes is respected on this forum, but I would have to strongly disagree that JJ 12AX7 tubes sound like a Black Plate or a 1964 Mullard. It ain't gonna happen.
Marty
MUSICIAN'S AUDIO EQUIPMENT-MAKERS OF VERSACAB