I just bought new tubes for my first tube amp and I'm trying to figure out how to bias it. The manual has a list of tube grades (A, B, C, D, E, F, G, and H) and what to bias it to for each tube grade. I just bought some Electroharmonix EL34's and I'm trying to figure out what tube grade they are. Please someone help me with this; I can't find any information on tube grades.
I've never heard of such a thing.

With Mesa Boogies I know their tubes have colors for identification but, that's for matching the tube set.

Outside of fixed biased amps, biasing is for each tube individually. A tube might be burning a good bit more than the rest, you bias it to the proper plate voltage.
Major of 7 String Legion 7 > 6

Carvin DC747
Ibanez RG2228
Schecter Avenger Custom Shop
and my baby....
Gibson Explorer Studio
I've always biased based on each tube's max plate dissipation.

What amp is this?