It's really disappointing not to be able to use my task light for its intended purpose. Mounted on the side of my turntable's dust cover, my wall-wart powered LittleLite induces a low-level hum into the cartridge circuit even when the lamp is turned off! Stranger still: the hum only starts when the stylus is lowered onto a spinning record! I'd understand that last bit if the vinyl record had metal impurities, because moving metal near cartridge windings could possibly induce a current of its own (the definition of an MM cartridge!). But the hum is there even on virgin-vinyl pressings.
Only when the wall wart is unplugged does the hum vanish. I haven't yet tried to plug the wall wart into a different circuit branch because an extension cord is unwieldy, not to mention un-pretty. And I refuse to run a dedicated line for just the lamp! :foottap:
Oh yeah, almost forgot - all gear, including the 'table and it's dedicated speed controller are plugged into an AC regenerator (PS Audio Power Plant Premier).
Only when the wall wart is unplugged does the hum vanish. I haven't yet tried to plug the wall wart into a different circuit branch because an extension cord is unwieldy, not to mention un-pretty. And I refuse to run a dedicated line for just the lamp! :foottap:
Oh yeah, almost forgot - all gear, including the 'table and it's dedicated speed controller are plugged into an AC regenerator (PS Audio Power Plant Premier).