Ok. Class AB.... Another question, since my amp head is 120watts and it runs 4 speakers in 8 ohms, is it possible just to run a 1x12 with the head? and what kind? I'm thinking practicality eh.
yes, it's possible, as long as:
1. the impedance matches (e.g. 8 ohm setting on the amp to an 8 ohm speaker, 16 ohm setting on the amp to a 16 ohm speaker.)
2. the speaker's power rating is 120 watts or higher.
the above is your rule of thumb. experienced users may mismatch impedances or use a speaker with a lower power rating, but i advise against this to avoid any problems or risks to your speaker/s and/or worse yet, to your amp.
eminence, fane, and jbl are some brands that have high powered speakers that you can try with your amp. unfortunately, it isn't exactly easy to find speakers that are 120 watts or higher, so your best bet might be to go with a 2x12 or 2x10 configuration with speakers that are at least 60 watts each (e.g. 2 celestion vintage 30's or 2 celestion classic leads).
hope this helps.
cheers.