Speaker hum from aquarium flourescent lights.

[JGPerryman]

I have significant speaker hum when switching sources on my Onkyo TX-NR709 receiver to the TV/CD analog inputs that I am using as inputs for my Rega RP1 turntable which is routed through a Musical Fidelity V-LPSII preamp powered by MF's V-PSUII power supply. The higher end AudioQuest RCA output cables from the preamp are connected to the TV/CD analog inputs on the receiver. There is a 55 gallon aquarium next to the component stand that houses my turntable which in turn sits next to the cabinet that houses the rest of my components...all within a span of about 12 feet in width. The aquarium lights are on a separate power circuit than my Panamax 5100 power conditioner, from which all components are powered. There is an AudioPrism Quietline noise filter plugged in next to the Panamax power conditioner plugat the wall outlet. When I turn the lights off, the hum stops. There are two flourescent fixtures with ballasts in the aquarium lid. Does anyone know of a solution to this problem? Would a flourescent fixture that does not require a ballast solve the problem?

Thanks for any help.

 

[jonnythan]

I expect it's not something coming through the power lines - it's the ballast itself.

I bet that if you plug the light strip into an extension cord and walk around the room with the light in hand, the hum will change as you move closer to the speakers.

If that's the case, the solution is to get a different light strip.

 

[JGPerryman]

You are correct. I removed the old flourescent fixture and replaced it with a two standard light sockets and 13W micro mini CFL bulbs by Sylvania. No more hum.

Thanks for your input.

 

[jonnythan]

Cool. A higher quality fluorescent fixture with an electronic ballast (like the T5 fixtures by Coralife) or one with power compact/CFL bulbs should also fix it. The cheaper ballasts are magnetic ballasts that create a pretty strong oscillating magnetic field that operates at 60 Hz. That's what the hum is - the ballast is creating a magnetic field that's making your speaker drivers move.

If you're using incandescents keep an eye on the water temperature. They can warm up the tank a fair bit.