Fender Rumble Series 100/210 100watt 2x10 Bass Combo Amplifier "bass amp makes hum noise" Questions

...bass knob way up) when I hit a hard low E, the amp pops once and the hums and makes some kind of descending cracle noise. turn it off and back on and its fine again. If I am gentle on the low E its ...

...bass amp with a similar problem last week: the problem is related to a loose connection on the PCB board (likely). A bass amp is a rough place for circuitry: the low rumble and power shake a bass amp ...