The Boss NS-2 noise supressor is designed for use in an effects chain. Generally, the more effects within the chain (or the more any one effect alters the instrument's sound,) the greater the chance of unwanted noise in the final mix. The NS-2 helps eliminate that problem. Different than most Boss pedals, it has send and return jacks as well as the standard input and output jacks. This means set-up using multiple effects units can be different than a typical pedal configuration, pay close attention when you hook up a Boss NS-2 noise supressor the first time.
Set up your effects chain in its usual configuration.
Remove any delay and reverb pedals from the effects chain. Set those pedals and their connector cables aside for now.
Reconnect the other pedals to one another in their usual order, completing the connection where the reverb and delay were.
Loosen the thumbscrew on the movable part of the NS-2 pedal, if you are using battery power, and open the pedal. Connect a 9V battery to the battery connector. Close the pedal and tighten the thumbscrew.
If using a power supply in place of a battery, connect that to the power jack of the NS-2 and plug in the power supply.
Test the NS-2 by stepping on the pedal once, then waiting a moment before stepping on it again. The indicator light should turn on when pressing the pedal the first or second time.
Plug an instrument cable into a guitar (or other instrument.) Plug the other end of the cable into the input jack of the NS-2.
Plug an instrument cable into the output jack of the NS-2 and connect the other end of the cable to the amplifier's input jack. If you are using a delay or reverb pedal instead, connect the NS-2 output cable to the input of the delay or reverb unit and plug the output of the delay or reverb into the amplifier's input.Turn on the amplifier.
Connect an instrument cable or connector cable to the send jack on the NS-2. Connect the other end into the input jack of the first pedal in the effects chain.
Connect another instrument cable or connector cable to the output jack of the last effects unit of the chain. Plug the other end of this cable into the return jack of the NS-2.
Set the threshold and decay knobs to their minimum settings by turning them counterclockwise. Set the mode knob to "Reduction."
Push the NS-2 pedal until the "Check indicator" light is on. Turn on the effects in the effects chain.
Turn the threshold knob until the "reduction" light is on while the instrument is silent.
Play a few notes on the instrument. Turn the NS-2's "decay" knob until note decay sounds natural.
The NS-2 can be used to mute the effects chain. Select "Mute" on the "Mode" pedal, and when the pedal is not lit up, the rest of the effects in the chain will be muted.