It depends on the specific MXR pedal model. Some MXR pedals are true bypass, meaning that when the effect is turned off, the signal passes through the pedal without any effect or alteration.
Other MXR pedals use buffered bypass, which means that even when the effect is turned off, the signal still passes through an amplifier circuit that can affect the tone.
It’s important to note that the type of bypass (true or buffered) can affect the tone and clarity of the signal, and it’s a matter of personal preference which type is preferred.
MXR offers a range of pedals with both true bypass and buffered bypass, so it’s best to check the specifications of the specific model you’re interested in to determine its bypass type.