I was playing with the band today - Yamaha TRB through Mesa Walkabout and when I pressed the switch on my bass-drive I heared quite noticable click from the amp. I switched on/off few times and every time I heared that click. I decided not to lose time and check it home. When i came home, I pluged my Spector bass (Yamaha belongs to our guitar player) through my home amp, switched on/off Fulltone for a couple of times and.... no click at all. What could it be?