Noise in guitar effects refers to unwanted sounds or interference that can disrupt the clean signal. This can come from various sources, such as electrical interference, grounding issues, or even the pedals themselves. Common types of noise include hum, often from power sources or fluorescent lights, hiss, which can arise from high-gain settings or amplifiers, and feedback, which happens when the sound loops uncontrollably between the guitar, amp, and effects.

Many guitarists use noise gates or power conditioners to reduce unwanted noise, while some pedals are designed specifically to manage or eliminate hum or hiss. Properly isolating your power sources and maintaining good cable management can also help reduce noise in your signal chain.