I don’t post too many entries in the “resource” category but when I came across this I was really excited. This site is chock full of easy to follow how-tos, tips, tricks, and tools that anyone in DIY audio (DIY anything actually) will find useful. I recommend adding the Curious Inventor Blog to your favorites and reading it frequently.
Music From Outer Space (MFOS) is an extensive resource for anyone involved in DIY audio. Anyone regardless of experience level should have the site permanently bookmarked as it has something for everyone. Although focused on DIY synthesis almost everything on the site can be used in your projects. One their most recent additions is their web tools, specifically their “web schematic“. From their site:
Ray Wilson at MFOS also provides a virtual breadboard designer, panel designer, and a few essential calculators including a Resistor Color Code Calculator, Parallel Resistance Calculator, Non-Inverting Op Amp Gain Calculator, Inverting Op Amp Gain & Offset Calculator, Comparator Calculator, and last an Inches to Millimeters Conversion calculator.