Can someone tell me how to turn off the chorus effect on a WK-7600? The first reverb option is "off" followed by all the available reverbs. But once you select chorus, you only can scroll from chorus 1 - chorus 5. There is no "off" option. Changing the dsp disable button to "on" or "off" doesn't make a difference. No matter what I try, there is always a black box next to "chorus" in the main display. Thank you