Jc-120 Schematic Verified -

Early revisions used discrete transistors, while newer models (like the JC-120H) utilize OpAmp-based gain stages for consistent clean headroom.

| Source | Notes | |--------|-------| | | Search “Roland JC-120 service notes” – sometimes free after registration. | | Synthxl.com | Has clear JC-120 scans (preamp, power amp, chorus). | | Elektrotanya.com | Free download after short wait. | | Music Electronics Forum | Archived service manuals. | | Schematic Heaven (archived) | Mirror sites still host old files. | jc-120 schematic

This schematic is frequently used as a reference but differs from combo models. It replaces the "Bright" switch with a "HI-TREBLE" pot and uses op-amp-based gain stages. | | Elektrotanya

The preamp section also features a range of switching options, including a channel selector, a gain boost switch, and a reverb switch. | This schematic is frequently used as a

These may use surface-mount components and different power supply configurations. Accessing Schematics

Roland no longer enforces copyright on these old schematics for personal use. However, if you plan to sell modded amps or PCBs based on it, consult a lawyer. For repair, always discharge power supply caps (±45V, ±15V) before probing.