manual by Teemu Kyttälä. These resources detail the progression of an electrical signal from the guitar pickup through the various stages of amplification to the speaker. Core Stages of a Guitar Amplifier
: Ripple voltage (PSU noise) – hum at 50/60 Hz or 100/120 Hz. Filter caps reduce it. guitar amplifier electronics basic theory pdf
: It takes the weak millivolt signal from the pickups and boosts it to "line level" Swee Lee Blog Tone Shaping manual by Teemu Kyttälä