| Era | Key features | Common ICs | |-----|--------------|-------------| | (Silver knob) | Discrete preamp, no reverb | 2SC458, BA662 (rare) | | 1980–1989 (Black knob) | Reverb added, FET input stage | MN3004, uPC1251 | | 1990–2006 (Mid boost) | Switchable mid, updated op-amps | NJM4558, MN3204 | | 2007–present (Reissue) | SMD components, no STK modules | TDA7293 (power amp) |
This article is a deep dive into the Roland JC-120 schematic. We will explore the history of its revisions, break down the signal path block by block, discuss common failures, and explain how to read the schematic to breathe new life into your classic amp. jc-120 schematic