I have an Echomax 2000 that produces digital noise such as high pitched whine with repetitive "clicking"(oscillating?) when the effects are used. No noise with effects off(center slot on knob) it also intensifies when the effects gain is turned up. It happens on both echo and slapback...the noise just sounds different. Has anyone experienced this and if so, what component caused it? Any help will be appreciated, 73s...Pluto.