~ Early Web Links ~

Mostly DIY RF is a specialized resource for amateur radio builders, offering PCB kits and detailed documentation for RF circuits including IF amplifiers, low-pass filters, VFOs, crystal filters, and MMIC amplifiers. The site covers designs by well-known ham radio engineers like Hayward and Kopski, making high-performance transceiver building accessible to hobbyists.

RED Free Circuit Designs is a hobbyist electronics resource offering dozens of free audio amplifier schematics, preamplifier modules, headphone amplifiers, and miscellaneous electronic circuit designs. Visitors can browse Class-A and Class-B amplifier projects, phono preamps, intercom circuits, and many more practical designs, all available at no cost.

RF Cafe is a comprehensive resource for RF and electronics engineers, offering formulas, reference data, vintage magazine archives, software tools, forums, and a massive parts and services directory. Running since 1996, the site blends technical depth with nostalgia, featuring scanned articles from classic publications like QST, Popular Electronics, and Radio-Craft alongside modern engineering utilities.

The Music Electronics µArchive is a long-running reference hub for DIY guitar effects and audio electronics, offering schematics archives, FAQs, and curated links to the best resources on the web. Highlights include a downloadable schematics archive, guides on tube amplifiers and transistor identification, and an Electro-Harmonix parts sheet for builders working with vintage pedal components.

Electronics 2000, created by Simon Carter, is a comprehensive hobby electronics reference packed with online calculators for resistors, capacitors, inductors, Ohm's Law, and more, plus technical data articles, pin-outs, and a beginner's guide. The site also offers downloadable Windows software like Electronics Assistant and an EPE Index, making it a genuinely useful toolkit for hobbyists, students, and engineers alike.

Electronics Notes, created and maintained by engineer Ian Poole, is a comprehensive reference hub covering electronics theory, circuit design, components, radio technology, antennas, ham radio, and more. With tutorials aimed at everyone from hobbyists to professionals, it also offers downloadable guides, infographics, and component data sheets, making it a genuinely useful destination for anyone working with electronics.

DMX512.com is a technical reference hub dedicated to entertainment technology, covering stage lighting, audio, communications, MIDI, show control, and power systems for theatre production. Named after the DMX512 lighting control protocol, the site organizes resources across multiple categories including net resources, reference materials, and even accident reports relevant to technical theatre professionals.