[netaron]

Hi all,
We have been remodeling for the past six or so months, so I haven't had a chance to listen to music. Anyways, las week I was finally able to hook everything back up and listen to some tunes. Well to my surprise, during a listening session my wife turned the kitchen lights on and there it was, a very loud hum playing through the system. I thought there was a problem with the power conditioner so I plugged everything directly into the wall, still no go. It seems if I disconnect my tube preamp, the hum goes away, but I would much rather turn the kitchen lights off.

By the way, the kitchen has recessed lighting which is comprised of six florescent  energy saver type lights.

Any thoughts and ideas appreciated.

Haron

[slbender]

Haron -

Of course you can't see if there is a ground fault, but maybe you are hearing one...  You could look into a $6 outlet tester, maybe the outlets are lacking a ground, or miswired.  Also the energy saving FL lights are likely putting harmonic crap onto your power line, and that is getting in through a mismatched ground or into your preamp if you are commonly grounded using a rack of some sort that commonly grounds all of the audio components. That can be nasty to get rid of. 

Assuming your preamp isn't some home-made tweako-nut job poorly implemented, badly grounded, and miswired...

First try replacing all the FL Lamps with ordinary bulbs, if that creates no hum, that indicates it originates from the FL's and likely is going into the power line on that phase.

Either switch to another leg of the phase, fix faulty miswired socket ground issues, or try a ground isolator on the preamp ( but also measure the AC potential between the preamp case and other components so you don't electrocute yourself next time you grab the volume control ).

Also the preamp could have faulty caps to ground causing leakage current, or if its a 2 prong plug, invert it and see if that helps.

Beyond that you'd need an electrician who knows how to track down these issues before you get zapped.

-Steven

Hi all,
We have been remodeling for the past six or so months, so I haven't had a chance to listen to music. Anyways, las week I was finally able to hook everything back up and listen to some tunes. Well to my surprise, during a listening session my wife turned the kitchen lights on and there it was, a very loud hum playing through the system. I thought there was a problem with the power conditioner so I plugged everything directly into the wall, still no go. It seems if I disconnect my tube preamp, the hum goes away, but I would much rather turn the kitchen lights off.

By the way, the kitchen has recessed lighting which is comprised of six florescent  energy saver type lights.

Any thoughts and ideas appreciated.

Haron

[AKSA]

Haron,

Stephen's advice is very good, I hope it works out.

Hum introduced onto the mains can be tricky to banish.  The fluro energy savers have inexpensive, built in high frequency supplies, and they can be quite dirty.  Try an X2 (mains) rated cap across the primary of the TLP transformer, too, around 220nF.  Short of that, precede the trafo with a common mode choke rated around 100mA at 120Vac, still using the cap across active and neutral.

Hope this helps,

Cheers,

Hugh

[netaron]

Steven and Hugh,


Thank you gents for your kind response; I will try replacing the bulbs first and see what happens.

Steven, I did use a power strip which tests for bad ground and the ground seems to be OK. The preamp has a three prong plug, so I can not rotate, but I will try to float the ground with Hugh's recommendation and see.

Thanks

Haron

[netaron]

OK,

Here is what I have found out so far:

The florescent lights are not the problem since the outdoor lights in the back yard are regular flood lights and they also create the hum issue when switched on. They are on the same circuit and the only difference is the frequency of hum is lower for the flood lights.

I also switched off the circuit breaker for the lights, but my audio equipment remained on, so the audio gear is on a separate circuit.

[netaron]

Issue solved,
It turned out to be a ground loop issue with my cable. Once I disconnected the DVD player form the pream, the noise was gone. I will get one of those inline filters to see if it works, if not, no big deal, I will use my system for Audio only.

Thank you for you help.


Haron

[AKSA]

Ah,

Haron, these things can so often be simple!!  I admit I never think of the simple stuff first, I tend to throw deep abstraction and wacky conclusions at it.......

TGIF,

Hugh