All wah pedals tend to be a bit noisy. I assume you're referring to a 'hissing' sound in the background. This is more apparent when the input signal is relatively low level. You can compensate for this (a bit), by raising your guitar volume, and lowering the input channel volume on your amp. I your guitar is already turned up full, you're pretty much stuck with it. This noise is more noticeable with some models than others. My Dunlop JH-1 can be a real 'pain in the process' sometimes.