/diy/ - Do It Yourself

Here's my situation for anyone who might want to help with advice or specific resources.

I'm unsatisfied with the synths I've played with, but lordy them modular setups get me worked up. I'd like to make a hobby of building my own, or assembling kits and stuff. Supplementing my setup now and then with purchases.

I've done a slight bit of soldering/circuits many years back, and when getting my math degree, I did some shit like solving diff eq's relating to electricity, but that doesn't help me at all to get started really. I just held off a $500 purchase of a synth, and am now looking to invest instead in tools and whatnot for being a proper /ohm/budsman. Not all of that 500 needs to get dropped immediately, I should earmark some of it for building a case or specific supplies I need for whatever I build in the future (LCD displays, rails, wood, ...)

So, what getting started resources and tools should I look into? I'd love a suggestion of parts and tools and tutorials and texts that would work well for a semi-beginner whose aim is synths and audio, with ~$200 budget.