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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 plug at 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.
 

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The lights are actually on a different circuit (different breaker)? If so, then you are probably picking up radiated noise, which can be hard to fix. If you are of a technical bent, or have a techie friend, bypass capacitors might help. Mu-metal shielding might help but may be difficult to apply (and costly to obtain), plus I do not know if the ballast transformer or lights themselves are the culprit. Lights without a ballast tend to use a high-frequency switching circuit which will change the frequency but may make the problem better or worse.


If you flip the hood so the ballast is on the other side (hopefully the opposite side), does it help?


Also note older lights and older ballasts may hum more than new, but again no guarantee a new hood would help...


Almost forgot -- does it only hum with the turntable? If so, you may have a grounding problem, which could be fixed with a separate ground wire from TT to preamp and/or main preamp, or may be able to move (physically) the cables from TT to preamp (and the preamp itself) and reduce the hum.


HTH - Don
 

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The culprit was the the ballast in each of the fixtures. According to info I received from another forum, evidently the ballast puts out a relatively strong magnetic field that oscillates at 60 hz. The lights were located close enough to the speaker drivers to actually drive the cones and create the hum. I removed the fixtures and replaced them with standard light sockets and two 13W micro mini CFL bulbs made by Sylvania. No more hum. The heat generated by the CFL's might be an issue, but I won't know until tomorrow when I check the water temp.


I just hope that my cichlids can adjust...:)


Thanks for all of your input...
 

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You should probably look around for daylight balanced bulbs...
 

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Quote:
Originally Posted by jerrygp  /t/1414797/speaker-hum-and-aquarium-lights#post_22116517


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 plug at 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?

First off, there are no such things as fluorescent lights that don't need a ballast. Fluorescent lights are at their core mercury arc lamps and they need some kind of current limiting which is what ballasts do, or they will destroy themselves. So the solution is not doing away with the ballasts, but which ballast if any will give you peace. Or, do away with the fluorescent lights.


I guess the modern alternative to fluorescent lights are LED lights and they could provide you with a solution, or not. If someone would sell them to you on approval, it might be an easy fix.


The ineffectiveness of the noise filter and power conditioner actually surprises me a little. The ineffectiveness of high end cables doesn't surprise me at all. Overall, it appears that the noise is either radiating into your system through EMI. or that it is exasperating a grounding problem.


Standing a thousand miles or more away, I'll go with EMI. It would be interesting to know if your florescent lights have magnetic ballasts or electronic ballasts. Switching ballast style might help. If the problem is EMI, it might be that a different RIAA preamp might help.
 
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