Audio technica at 4040 constant ground hum noise

You could try another power adapter on the receiver, maybe this one blew the filter capacitor. I doubt your problem being the mic, rather check the receiver. Luck !

Is the grounding cable attached to a real ground connection?

For anyone googling this, to take apart the audio technica pro 45 just peel off the sticker on the bottom to remove the three hidden screws. Everything then just slides out the bottom.

It hums because it doesn't know the words (I crack me up).

Do you mean physical hum at the unit or audio hum through speakers?

BTW: no make or model number info came through with your post.

Disconnect the input(s) and see if it hums in the absence of an audio source. A bad audio cable shield or unwisely-routed audio cables will allow entrance of unwanted signals from external power sources, magnetic fields, even dimmer-controlled track lights. Sometimes, simply reversing the orientation of the ac power plug can eliminate humming.

Reverse the cables Left to Right to see if it stays with the cable or the input channel. Follow it back to the source, isolating in the same manner. Eventually you will find the entrance point of the hum. Freqquently a cable

How to isolate annoying background hum.

As long as the music or movie is playing, you can forget about it, at least until a quiet passage occurs, then there it is again: HUMMMMMMM! Be gone, bad hum, you think. But, like a bad odor at the back of the fridge, it takes some dogged persistence to track it down and eliminate it.

Hum is a constant low-frequency buzz, usually at about 60 Hz or 120 Hz, which results from voltage differences between true "ground" (what you'd get shoving a copper pipe into the ground) and the electrical "ground" of your receiver's chassis, the incoming cable-TV feed, or any video or audio components interconnected within your system, including powered subwoofers. When this voltage differential exists, it's called a "ground loop," and the hum it produces is darned annoying. You'll hear the hum mainly from the subwoofer because it's a low-frequency noise, but there will also be hum from your floorstanding front speakers or even compact bookshelf models.

First, try disconnecting your subwoofer from the coaxial sub cable from your AV receiver but leave the subwoofer turned on. Does the hum go away? If it does, then the ground loop is entering the system from your AV receiver and/or your cable-TV system set-top box (or satellite dish and decoder).

Disconnect the incoming TV-cable or satellite feed to a set-top box or to your TV and the A/V receiver. If the hum disappears (and you don't use a satellite dish) complain to the cable-TV company. They may know what you need and supply you with a ground-isolating transformer. If they don't know what you are talking about you'll need to order a video ground isolator and install it in-line with the TV cable before it enters your set-top cable-TV box. Axiom has special wide-band isolation transformers that will not interfere with any digital TV or HDTV signal. (N.B. You CANNOT use one of these with a satellite decoder box.)

Before you order one, you can try plugging your subwoofer into a different AC outlet in the room, ideally one that is not on the same circuit as your AV receiver and video equipment (TV, DVD player, sat or cable TV box, etc.) That may solve the problem. If it doesn't, see if the back panel of your sub has a "ground-lift screw". It will be labeled as such. Just remove it. That may remove the hum. If it doesn't and you have a standard cable-TV feed (not a dish), then order the ground-isolation transformer. (Axiom has special wide-band isolation transformers that will not interfere with any digital TV or HDTV signal.)
Axiom Audio Ground Isolator

If that still doesn't eliminate the hum, or if you use a satellite dish video feed, then you could try one of these from Radio Shack, which goes between the subwoofer and the coaxial cable from the receiver's subwoofer output.

With persistence, all ground-loop problems can be solved.

Hope it helped..

Have a nice day...

Sounds like a phantom power issue. Good Luck, Cody J.

Remember this is a condenser mic that REQUIRES phantom power. There are several failures regarding this phantom power delivery that COULD cause your problem.

A "LEAKY" mic cable that is not a fully balanced cable can cause the problem. Test with another cable to exhonorate your cable.

A failure of the input bypass caps in your amp/preamp can cause the input to become unbalanced and let in hum.

A phantom power that is improperly filtered can also cause this. Test using a different source of phantom power.

Remember that you can easily get feedback that may oscillate like hum if you have a monitor speaker anywhere in "earshot" of the mic. They are very sensitive and intended for studio use.

does the hum occur when playing a dvd or only when watching tv ? if the hum occurs only when watching tv, i would like you to disconnect the cable line from either the wall or the back of the cable box and see if this hum disappears. if the hum disappears call your cable company. you have what is called a " 60 cycle ground loop ". hope this helps.

Hi...
Get new audio cables . It seems there's a broken Ground (shield ) wire somewhere in the cable. NO ground means HUM usually

CHECK THE ALL THE CABLES (RCA) .
i think missing ground sheeld .
or smoothing capacitors are leak.or power output section faulty.
can you poen the cover and check circuit board get wet anyhow,
nuwan