retube

Hello I am newcomer here so just happy to join to community! So its about time to retube my ENGL Fireball, i have some electrical work background but never opened guitar amplifier, i have set of new tubes but how difficult is to bias this head, is it better just to take to tech, i am trying...

Hey I dont know a thing about tubes... but from what ive read JJ's and Rubys are the best for a 5150. Im thinking a combination of both, but i dont know what models to get, and where to put them in the amp. What do you recommend?

I feel it is time to re-tube. I like the tone of my head already but alot of people say if you put the right tubes in these and adjust the bias (which i have no knowledge of) this amp will sound much better than stock. for tonal improvements i would like it to sound less grainy and a little...

Man, I am slightly confused at the moment, but hey, anyway... What I want to do: - A new set of valves for the triaxis (it's been a good 3 years since it had any, and I think they are just stock mesa's) - Possibly a set for the UL, although if they can remain stock and if i can replace 1-3...