There are some cold joints on there. Take the time to reflow your solder and make sure it pretty much sinks in to the hole instead of sitting in a ball on top.
So, I've finally got around to the artwork on this one. I kept the temporary knobs and worked around that. The artwork is my attempt to hand paint something pixelated and it shows. I waited months for the art inspiration as well as nicer weather to rattle can some primer and gloss. This is still...
Breadboarding isn't hard. You just have to do it and think a bit differently than "solder by number". There's a bit of a puzzle involved. For a simple SHO it won't be difficult. There are tons of pics in the Test Kitchen to go from schematic to breadboard. It's a good skill to learn if you're...
An overgeneralization, but the larger the speaker, the more low end and more volume can go through. More speakers do not necessarily mean more volume. In other words, going from a 2x12 to a 4x12 doesn't mean your cab it 4x louder.
IPA and a toothbrush will work just fine. Doing it once will give you decent results, but like OP said there is still some residue. Simply clean it again.