The pitch of the entire signal is modulated up and down by a Low-Frequency Oscillator (LFO).
Unlike traditional tube amplifiers, the JC-120 relies entirely on solid-state components. The schematic is divided into several main sections: the dual preamps, the built-in effects loop, the stereo power amplifier, and the specialized analog chorus/vibrato circuit.
| 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. |
Generally a mono spring reverb tank, though some schematics show it could be modified for stereo-like separation.
Solid-state amps run cleanly, but aging electrolytic capacitors in the power supply section degrade over time. Check the schematic for the main filter capacitors (usually large caps rated at 50V or higher) and test them for ESR (Equivalent Series Resistance).
The pitch of the entire signal is modulated up and down by a Low-Frequency Oscillator (LFO).
Unlike traditional tube amplifiers, the JC-120 relies entirely on solid-state components. The schematic is divided into several main sections: the dual preamps, the built-in effects loop, the stereo power amplifier, and the specialized analog chorus/vibrato circuit. jc-120 schematic
| 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. | The pitch of the entire signal is modulated
Generally a mono spring reverb tank, though some schematics show it could be modified for stereo-like separation. | Source | Notes | |--------|-------| | |
Solid-state amps run cleanly, but aging electrolytic capacitors in the power supply section degrade over time. Check the schematic for the main filter capacitors (usually large caps rated at 50V or higher) and test them for ESR (Equivalent Series Resistance).