Jc-120 Schematic !free! Now
For those looking to personalize their JC-120, the DIY community has created a few notable modifications.
A streamlined clean path featuring High and Low inputs, a Bright toggle switch, Volume, and a 3-band (Treble, Middle, Bass) passive tone stack.
What are you troubleshooting (hiss, no chorus, dead channel)? Share public link jc-120 schematic
At its heart, the JC-120 is unique. While rated at 120 watts, it uses a "twin-amplifier" configuration where each of its two 12-inch speakers has its own dedicated 60-watt power amplifier. This design is fundamental to achieving its true stereo chorus effect.
Early models are sometimes described as having a slightly warmer, more organic tone due to component tolerances and early discrete component designs. For those looking to personalize their JC-120, the
When an old JC-120 starts to hiss, crackle, or lose its magic chorus swirl, the JC-120 schematic becomes the most valuable tool in a technician’s arsenal. In this article, we will dissect the architecture of the Jazz Chorus, explore its critical failure points, and explain why reading the schematic is essential for restoration.
is not a standard guitar amplifier. It operates as a true stereo system from the preamp output to the speakers. Circuit Type Key Component Solid-state Op-Amp 4558 / Custom Op-Amps Clean gain and active EQ filtering Modulation Analog Delay Line MN3007 BBD & MN3101 Clock Creates the analog chorus and vibrato Power Amp Bi-polar Transistor (BJT) Dual discrete push-pull stages Drivers 2x60W channels independently Deconstructing the Schematic: Section by Section Share public link At its heart, the JC-120 is unique
Provide a for measuring bias voltages on the power board.
The Roland JC-120 Jazz Chorus schematic Go to product viewer dialog for this item.
The Roland JC-120 Jazz Chorus is a legend. Since its debut in 1975, its unmistakable "JC Clean" tone and lush stereo chorus have defined the sound of guitar for nearly five decades. Unlike many iconic amps that rely on warm tube saturation, the JC-120’s all-transistor design is celebrated for its pristine, powerful, and untouched reproduction of the guitar's natural voice. However, for the owners of these venerable amps, the key to their longevity lies in understanding their complex circuit, a task made challenging by the fact that the JC-120 was produced in a number of distinct revisions.
