The BirdStone Sound Project is a completely open source development tool for guitar amplifiers and other types of audio gear. Taking the guesswork out of the design process making amplifier building more widely available to everyone.
Using the BirdStone modular development system, you can easily design your own amplifiers, or other audio equipment, using this completely open source hardware system. There are power supply modules, preamp modules, tone stack modules, and others. You can use these modules with interchangeable pieces to tweak the design and shape your tone.
Once you have finalized your design, use the open source hardware schematics to document your design, then you can build it in a single enclosed unit if you want and style it any way you like.
It doesn't matter whether you want to build vacuum tube or transistor equipment, it makes no difference. There are open source modules for each type, and some (like tone stacks) will work for both types of equipment. You can combine a transistor power supply module and a transistor output module with a breadboard and components of your choice and you have a full fledged development environment!