So I've got a Peavey Classic 50 head and it's time to get some new tubes. I looked on the back and it said it has 3 12AX7A's and 4 6BQ5's. I can't find anything but two tubes on SamAsh.com that are 12AX7A's and one tube for the 6BQ5's and it is a Sovtek EL84 6BQ5. So my question is are 12AX7As the same thing as just 12AX7s? And is an EL84 the same thing as a 6BQ5? Because I just find it strange that I could find almost nothing for these on both Samash and musiciansfriend. Any help would be appreciated so thanks in advance.

The preamp tubes listed are the kind of the same but will sound a little different, such as a little darker/more trebley/etc. not 100% sure on what the difference between those two are

The EL84's are the European name for 6BQ5 (<-- American classification) and vice versa

Also check here: https://www.ultimate-guitar.com/forum/showthread.php?t=473149
and here: https://www.ultimate-guitar.com/forum/showthread.php?t=278232

YAY for stickies