Keep building. Keep tweaking. Keep the analog dream alive.
The Carbon Copy’s modulation comes from a Low Frequency Oscillator (LFO) —usually a dual op-amp configured as a triangle wave generator. This LFO voltage is summed (added) to the "Delay" knob voltage. So, even if you don't touch the knob, the clock speed is subtly wobbling up and down. That wobble creates the pitch warble we call modulation. Section 4: The Output Stage & De-Emphasis After the BBD, the signal is a mess. It contains your delayed audio, but it’s a "staircase" waveform full of high-frequency clock noise (usually around 10kHz–30kHz). The first thing after the BBD is a low-pass filter (the reconstruction filter). This smooths the steps back into a sine wave and kills the clock whine. Mxr Carbon Copy Schematic
Then, the signal goes back into the . This is the expander . Remember how we compressed the signal earlier? The expander does the opposite. It turns quiet signals down and loud signals up to restore your original dynamics. Keep building
A BBD chip has a limited headroom. If you hit it with a hard pick attack, it will clip into ugly, splatty distortion. The compressor gently squashes your dynamics so the BBD sees a consistently strong, but not too strong, signal. The Carbon Copy’s modulation comes from a Low
The delayed (and compressed/expanded/filtered) signal goes through the . This is a simple voltage divider. When the Mix is at noon, you have equal parts dry and wet. When it’s maxed, you have only the wet signal (great for using the pedal as a weird vibrato unit).
In this post, we aren’t just going to stare at a schematic; we are going to break it down block by block. Whether you are a DIY builder looking to clone it, a modder looking to tweak it, or just a curious player, understanding the Carbon Copy schematic is a masterclass in modern analog delay design. This post is for educational purposes only. The MXR Carbon Copy is a patented, copyrighted design owned by Jim Dunlop. Do not use this information to manufacture pedals for commercial sale. The Big Picture: What Makes the Carbon Copy Special? Before we dive into the resistors and capacitors, let’s look at the signal flow. The Carbon Copy is a BBD (Bucket Brigade Device) based analog delay . At its heart is the CoolAudio V3205SD, a modern reissue of the legendary Panasonic MN3205.
But what is actually happening inside that die-cast enclosure? How does a 40-year-old bucket brigade chip create such a sought-after "vibe"?
Keep building. Keep tweaking. Keep the analog dream alive.
The Carbon Copy’s modulation comes from a Low Frequency Oscillator (LFO) —usually a dual op-amp configured as a triangle wave generator. This LFO voltage is summed (added) to the "Delay" knob voltage. So, even if you don't touch the knob, the clock speed is subtly wobbling up and down. That wobble creates the pitch warble we call modulation. Section 4: The Output Stage & De-Emphasis After the BBD, the signal is a mess. It contains your delayed audio, but it’s a "staircase" waveform full of high-frequency clock noise (usually around 10kHz–30kHz). The first thing after the BBD is a low-pass filter (the reconstruction filter). This smooths the steps back into a sine wave and kills the clock whine.
Then, the signal goes back into the . This is the expander . Remember how we compressed the signal earlier? The expander does the opposite. It turns quiet signals down and loud signals up to restore your original dynamics.
A BBD chip has a limited headroom. If you hit it with a hard pick attack, it will clip into ugly, splatty distortion. The compressor gently squashes your dynamics so the BBD sees a consistently strong, but not too strong, signal.
The delayed (and compressed/expanded/filtered) signal goes through the . This is a simple voltage divider. When the Mix is at noon, you have equal parts dry and wet. When it’s maxed, you have only the wet signal (great for using the pedal as a weird vibrato unit).
In this post, we aren’t just going to stare at a schematic; we are going to break it down block by block. Whether you are a DIY builder looking to clone it, a modder looking to tweak it, or just a curious player, understanding the Carbon Copy schematic is a masterclass in modern analog delay design. This post is for educational purposes only. The MXR Carbon Copy is a patented, copyrighted design owned by Jim Dunlop. Do not use this information to manufacture pedals for commercial sale. The Big Picture: What Makes the Carbon Copy Special? Before we dive into the resistors and capacitors, let’s look at the signal flow. The Carbon Copy is a BBD (Bucket Brigade Device) based analog delay . At its heart is the CoolAudio V3205SD, a modern reissue of the legendary Panasonic MN3205.
But what is actually happening inside that die-cast enclosure? How does a 40-year-old bucket brigade chip create such a sought-after "vibe"?
