Hey, UG forum, I'm past overdue for a tube change, however upon looking for advice to which model tube I should replace mine with, I realized there is no tube thread or I cannot find it.

So, I've been playing a lovely Peavey Windsor Studio, mostly being used for recording, but I've got some sizeable gigs coming up this summer when my band regroups from college. It comes loaded with 2*12ax7's in the pre and an EL34 as the power tube.

This amp is accessible with pretty much any tube availibe, and I'm looking to replace the EL34 (the pre's are in okay condition), so what does UG suggest, what do different tubes sound like or where should I head to find this info?