8.6 The guitar amplifier as a project

I declare: solidlikelyshaky

1. Write the specification: power, high-impedance instrument input, gain and wanted overdrive, tone control, outputs, supply.
2. Draw the block diagram: input, preamp, overdrive, tone, power stage, supply, and the levels between blocks.
3. Choose a topology per block among those that exist (op-amp or JFET preamp, passive tone stack, class AB or integrated-chip power) and justify.
4. Prototype block by block, each measured alone, then connect them and measure what changed.
5. Put it in an enclosure: grounds, shielding, heat, wiring of pots and jacks, and the noise that comes from a badly made enclosure.
6. Compare your schematic to a commercial amp’s and say what the industry does more or less, and why.
7. Diagnosis: a guitar amp that hums when you touch the strings or whistles at high volume, instrument ground, input wiring or feedback through the enclosure.