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HUM - you can catch fish in a dingy too.

You can go buy a six-figure bass boat to catch fish, but you can catch the same fish out of a $200 rowboat.

So, I had - HAD - a hum problem in my system that was driving me nuts for about a year. It started out that it was the amplifier making the speakers hum even when the source or pre-amo was disconnected. Then I got a new preamp and the amp was quiet but the hum returned as soon as I took the preamp off mute - basically the hum jumped components, which left me drooling in rage and confusion. I switched sources, switched cables, switched ICs and speaker cables, added a power supply then plugged everything directly into the wall.... Arrrggghh!!!

Finally, in desperation I did something that I don't like for a number of reasons: I stuck a 35 cent cheater plug between the pre-amp and the power supply (which is itself still grounded) and the hum FINALLY went away. $15,000 worth of audio jewelry and it took a 35 cent piece of plastic to make it work right. Sometimes we are too smart for our own good. Just thought I'd share.
grimace
mofimadness's avatar
mofimadness
4,993 posts
 
Sorry you struggled for so long with this problem. A cheater plug should have been one of, (if not the first) things you tried.

I have several of these within reach to eliminate such a problem. I have used them a few times and usually they work just great.

Glad you traced down and solved your hum problem.
sandstone
358 posts
 
Good find, but you may still not be home free. Some of the experts here might wonder if you could be placing your $15K system at additional risk. You may want to check some of the old Agon threads regarding cheater plugs.
The good news: this may be a great diagnostic clue on how to solve this (grounding problem?) without the cheater plug.
mlsstl
1,438 posts
 
One other suggestion - buy a polarity (outlet) checker and make sure the wall socket is correctly wired and grounded. If it isn't, not only could that cause the hum, but it also creates a shock hazard. The checkers are $5 or so at hardware stores.
newbee
4,767 posts
 
Cheater plugs are a poorly kept secret I think. I've used them off and on for years usually on a pre-amp/amp combo keeping at least one properly grounded. I disregard the braysayers regarding risks. Interestingly yesterday I was reading a highly regarded amp designer/manufacturer's comments about how to avoid hums - use cheater on pre-amp. And he wasn't the first either.

FWIW I just went thru a hum problem. A real PITA but ultimately I found that the hum was corrected after I used a cheater on all of the sources ahead of the (integrated) amp. I think the amp may have an inherent design issue. I've never had this problem before with either a pre-amp or an integrated amp.
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