Boss CS-3 Compressor/Sustainer modified by Humphrey Audio (often called the “Atom Smasher” mod). This mod replaces the cheap stock components to eliminate the famously noisy hiss, restore warm low end, and provide a rich, transparent, and quiet compression tone. 

**KEY BENEFITS**:

• Quiets the Circuit: Drastically lowers the hiss and noise floor that makes the stock pedal notorious.
• Transparency: Prevents the overly squeezed, "splatty," or muffled sound characteristic of the factory CS-3.
• Low-End Retention: Restores warm low frequencies that standard compression often neutralizes.
• Increased Headroom: Improves the overall clarity and functions as a clean boost pedal. 

**HUMPHREY MOD CONTROLS**:

The pedal retains the 4 standard knobs, but they perform much more musically after the mod: 

• Sustainer: Increases sustain without introducing artificial coloring.
• Attack: Controls how quickly the compressor reacts to your string pluck. The Humphrey mod makes this much more responsive and dynamic.
• Tone: Because the mod opens up the low and high frequencies, this active control allows you to shape your brightness without killing depth.
• Level: Controls the overall output volume, with more usable clean headroom on tap.