Can the speakers be upgraded on the Code 412 cabinet? If so, is it something a person can do who’s never changed a speaker before, or would it need professional installation?
Very simple. I upgraded as I use 7 and 8 strings so the low end was not good. Make sure your speakers are 12 inches an are at 8 ohm with a 50 watt min per speaker. You can go up in watts like I did with my Eminence Man O Wars and Wizard speakers. Take lots of pictures before you start and do one at a time. Once you have the back panel unscrewed do not pull off the panel, only open enough to see how your cab speaker jack is connected then you can disconnect it. I almost ripped out my speaker jack and wiring doing it. Here is my before and after rig.
If your looking for more tones check out this site for 1000s of presets. https://marshallcode.tools/
I went with Eminence for price and USA made. Celestions are great but you gotta pay for them. I got my speakers from Sweetwater and they will shake walls literally.
Wow — thanks for the detailed answer! I recently got the Marshall Code cabinet and head from Sweetwater, actually. I'll look there for speakers, as you suggested. Great information. You rock :)