7025 v. 12AX7

[mbratch]

I know these tube types are basically interchangeable. I've also read in places that the 7025 was a lower noise version of 12AX7 (?).

But whatever the subtle difference, why did Fender call out both of these tube types in different parts of their BF amp circuits in the particular places they did?

Just curious... :)

[rooster]

Back in the day (50's and early 60's), the 7025 was indeed a lower noise version. However, the tube companies all stepped up to the plate so that all 12ax7's were built to the 7025 spec. However, with new tubes, it's marketing. The new tubes are all the new tubes, and you'll have the most satisfaction with the ones you like best. Real helpful, eh?

Or, you could ask Mike at KCA tubes. He's one of the best. Personally, I use JJ ECC803S's for first stages, and JJ ECC83's for the rest, but I've heard good things about TungSol. I've yet to find anything that measures up to my old Bugleboys and Mullards, but I like the "english" tone. For Fendery stuff, I like old RCA the best, sometimes GE, and TungSol.

Old Tungsram seem to work great in any amp.

rooster.

[rockon1]

Personally, I use JJ ECC803S's for first stages, and JJ ECC83's for the rest

rooster.


Ah,a personal new production combination favorite of mine! The ECC803 adds a little sparkle and the ECC83's keep things fat and warm. JJ's are the only NP I'll consider using anymore although I run OS these days.
As for the question I can only imagine Fender wanted a tube with lower noise in parts of the circuit where it might be more critical such as the initial gain stages.