Given that the powered subwoofer hum requires RCA connection with the amplifier, and powering both the subwoofer and the integrated amplifier from the same multiple outlet, heavy duty extension cord has no effect on the hum, is a subwoofer isolation transformer still a possibility for hum reduction/elimination?
Details: 60Hz or 120Hz hum in Klipsch 10-SW powered subwoofer connected to Line Magnetic 210IA integrated amplifier (no external preamp in system)
Power cord on subwoofer is: (1) two pronged at male end and (2) hardwired at subwoofer end.
Thank you!
Hum frequency | Could be piano B2 (~ 120 Hz) or
Piano B1 (~60 Hz) –
very hard to discriminate |
With no subwoofer RCA input | No hum |
Add subwoofer RCA input from Line Magnetic amplifier | hum |
Change Line Magnetic
Amplifier volume setting | No effect on hum |
Change Line Magnetic
amplifier source selector | No effect on hum |
Disconnect all Line Magnetic
amplifier RCA inputs | No effect on hum |
Power Line Magnetic amplifier and subwoofer amplifier into
same extension cord | No effect on hum |
Multiple Repositioning:
amplifier to subwoofer RCA interconnects position with respect to all power chords | No effect on hum |
Change amplifier to subwoofer
RCA interconnect cables | No effect on hum |