Problem with mains hum

[nomy]

Hi.

 

I have only recently started recording again after a gap of a few years. We are now in a different house and I am getting some annoying hum from ANY guitar plugged into my little Zoom MRS1266 studio. I would kind of expect some when using a heavy distorted fx on lead guitar but when using my Yamaha APX 5A with no fx it's a steady low frequency hum, which kinda suprises me as I wouldn't expect it from that. It only stops when I touch the input jack.

 

I have tried all kinds of leads, different sockets etc, but to no avail.

 

Any ideas how to stop this?

 

Many thanks.

[nomy]

No ideas anyone? I'm especialy interested in how just touching the metal body of the jack will completely stop the hum, even when I'm not earthed.

 

The hum is not the usual kind that varies as you move around. THis is a steady unchanging low frequency hum.

 

I'm really desperate here. It's preventing me recording and I need to record the guitar bits.

[Herb Hunter]

It sounds like you have a ground problem. It is not uncommon for houses or buildings to have improper wiring. Radio Shack and Home Depot both sell a grounding tester for well under $10. Using such a tester you can check to see if your outlets are properly grounded.

 

If you have a three prong plug and have defeated the third prong so that you could plug it into a two prong outlet the result would be the same as faulty wiring. The noise you are hearing is 60 hz AC hum. It stops when you touch the metal on your guitar because your body provides a ground of sorts.

 

This video illustrates what I just wrote about:

 

http://www.taylorguitars.com/video/noise-reduction.aspx

 

I'd like to know if any of this solves your problem so keep me posted.

[fantasticsound]

Yep! You only think you're not grounded enough to quell this 50Hz/60Hz hum. (In the UK it would be 50Hz, in the U.S. it is 60Hz.)

 

Try wrapping or soldering a piece of wire to the barrel of your 1/4" plug and run the other end to something that can ground the jack. You have a floating ground somewhere, and it may or may not be caused by the electrical connection powering the unit. It may be an internal issue, either damage or poor design.

[kwakatak]

I get this all the time with my rig too. Usually the halogen lamp causes the buzzing, but not always. Sometimes it's the PC.

 

It ticks me off because I can't turn the levels up very high and I have to try and augment the raw track somehow in Audacity.

[d28andm1911a1]

Strange noises sometimes have strange causes.

 

I have a 30 run to the computer from the mixer and I get a click click in the recording but not in the live sound. Took me a year to find that the 30 ft run to the computer was an antena that was picking up the pulse of the electric fence.

 

I can fix it by having the 30 run take a couple of right angle turns or turning off the electric fence.

[fantasticsound]

Halogen lamp, Neil??

 

Get a battery powered lantern or use candles when you're recording.

 

As for the computer, you just have to move the audio portion of your front end away from the computer and check the grounding everywhere. Are you recording to a dedicated, pro-audio soundcard or into the 1/8" jack on a Soundblaster compatable, OEM soundcard? If it's the latter, you're screwed.

 

d28andm1911a1, my suggestion would be to get a set of isolation transformers, a la Ebtech's Hum Eliminator box. Then you can run a balanced line between mixer and these boxes, and an unbalanced line for only a few inches by the computer. (This assumes you have a real, differentially balanced output on your mixer. Then, if the click, still existed, from the short jumper, at least you could shield the entire jumper with aluminum foil, grounded to something.

[kwakatak]

Originally posted by fantasticsound Halogen lamp, Neil ?? Get a battery powered lantern or use candles when you're recording. As for the computer, you just have to move the audio portion of your front end away from the computer and check the grounding everywhere. Are you recording to a dedicated, pro-audio soundcard or into the 1/8" jack on a Soundblaster compatable, OEM soundcard? If it's the latter, you're screwed.

 

Hehe - maybe I'll light a ton of candles and burn the incense. The blacklight and lava lamp will probably make that damned hum anyway!

 

BTW - yes, I'm using the 1/8" jack but that's another issue. I agree that I am screwed anyway!

[fantasticsound]

Yeah... I'm still recording through a damned OEM soundcard at home, too. Noise does abound from such a connection. The worst, for me, is that much of the noise is not evident on recording, so it's difficult to know how much noise will come through when I render files to a stereo master and burn them to CD.