Re: I got a Marshall 2558 Jubilee 2x12 combo! Questions inside...
You have the the one that was exported to Canada. I can tell since yours has the metal toggle, which honestly is a better switch than the plastic red one.
I haven't checked Marshall parts, but I'm not sure they'll have the silvercapped ones.
Hopefully, they do. I have the 2550 head and two 4-12's, and am hanging onto it as a great amp to play and for collectibility sake. These will prove to be the most collectible Marshalls, outside of the early P to P amps in great shape.
I've messed quite a bit with tubes and bias on Jubilees. I use Tesla JJ E-34L's biased around 38mA and Sovtek 12AX7LPS, and mine smokes. The GT12AX7C's will sound perfect, too. I tried the expensive GT12AX7M's, and it added some gain, but the C's sound tighter to my ears. The LPS's are Sovteks best tube, and they sound great in highgain amps as well. Congrats....I'd love to have your combo. A part of me wishes I had ALL the Jubilee models in a collection, but I can't afford that endeavor.