Recently bought GT -12AX7C

[Strat N My Stuff]

I picked up a Gold GT12AX7C, to put in V2, following a Gold GT12AX7M in V1. LSS amp. Another post led me to read about the GT ratings which I hadn't even considered. Does that even apply on these tubes? Where do I find the number? I've used the M in V1 without problem, at least that is readily apparent.

 

[phyrexia]

I don't think they rate preamp tubes like they rate power tubes.