I bought a Boss 900cd recorder on ebay, and customer service has not been much help. I think my questio0n applies to any brand of recorder. If I do not use any effects for guitar, the sound is fine. But when i push the effects button, and whether I use the preset distortion or the preset clean tones, I get a hum and/or buzz noise. It is present only when the strings are making noise. Any amount of noise made from the string and you can hear interference, but if the strings are silent, there is no noise. I thought it may be from power lines, so I went out of town away from power lines, and it is still the same. So my question is, does anybody else have this problem with their recorder? Thanks.