Hi guys! Just came back from day two of my big guitar hunt through the major stores of Delhi with another question: The store I visited today had a lot of background hum audible through the amplifiers. The clerks blamed it on "Earthing noise". The hum was loud with some guitars (Eg. the Squier California strat) and absent with some (Such as the Avion AV1) The hum was heard with some pickups and not heard with others (But humbuckers were not exactly immune to it) The hum was louder with some amplifiers (almost deafening with Marshall 15cd) and lesser with others (Expensive Laneys seemed to "fix" it) So I'm asking here what are the possible causes of hum and what was the cause of the hum I heard. Also, how to assess how quiet a guitar's electronics are with problems like this? I should mention that the hum problem was much worse in this store than a store I visited yesterday. Thanks guys!