Help with noisy cable connection

Colox · 05-18-2019, 08:29 AM

I got this quite noticeable noise coming through my mic cable, though it is an XLR connection (with 48V fantom). It's like a low level static noise, together with what sounds like a highpass-filtered ground hum, which phases and fluctuates all the time.

But if I touch the casing of my soundcard, or just the metal casing of the XLR connector, then the noise slowly disappears (to at least 80%) over a 2-3 second fade out. I gotta touch the metal parts though. If I let go, boom the noise is back instantly.

I've made sure that the cable doesn't run close to any transformers, powercables, screens, Fluorescent lamps of any kind etc. And my soundcard is hooked up to the powergrid through a grounded outlet.

What is causing this BS?
Thx

bucca · 05-18-2019, 04:11 PM

all cables, or just that particular one? checked the soldering points? Just a guess.

grinder · 05-18-2019, 05:10 PM

Try another cable does it do the same thing?
If it does the fault most likely be elsewhere in the chain.

Grinder

Colox · 05-19-2019, 12:38 AM

Quote:

Originally Posted by bucca

all cables, or just that particular one? checked the soldering points? Just a guess.

Just this one. I didn't notice until you asked.
I think the soldering points should be good, it's a brand new cable. Also it's not possible to check because these connectors are closed, solid rubber/plastic, not able to open.

Stella645 · 05-19-2019, 01:24 AM

If it's just this cable and other cables work ok in the same connection then the cable is bad. Nothing you can do about it if you can't open the plugs.

Colox · 05-19-2019, 03:33 AM

Quote:

Originally Posted by Stella645

If it's just this cable and other cables work ok in the same connection then the cable is bad. Nothing you can do about it if you can't open the plugs.

Damn.

It's a headmounted lavalier mic. It's got an XLR but quite probably the cable isn't shielded properly, or the balancing doesn't work. If I hook up my SM58 through a regular XLR cable, there's no problem. Though it does deliver 48V to the lav mic properly. Weird.

Makes me think I need to cut the enclosed wire off (void the warranty) and see if I can solder myself out of the problem, solder it to a regular XLR connector. Talking to the manufacturer is usually a waste of time.

grinder · 05-19-2019, 12:15 PM

In NZ a couple of years ago I purchased several cables from a firm I had had great service from and had purchased many many cables from XLR and Jack.
The cables arrived I took them from the wrappings they were almost like sprung steel they were stiff as boards and straightening them was impossible.
These cables plugged in passed a signal but ever ytime the cable
there were scratching sounds in the wave file and from an amp.
I did not send them back it is a policy of mine to move on.
This said the next batch I brought from a different retailer was
faulty as well looked great faulty wires.
I ended up going to Music Planet purchased a couple and they are fine.

Just because things are new means nothing.

Grinder

Stella645 · 05-19-2019, 12:55 PM

Quote:

Originally Posted by Colox

Damn.

Makes me think I need to cut the enclosed wire off (void the warranty) and see if I can solder myself out of the problem, solder it to a regular XLR connector. Talking to the manufacturer is usually a waste of time.

If it was only a cable I would agree. For a mic with fixed cable I'd be trying to get sorted on the warranty first.
Though if it's an Ebay no-name type product rather than a known brand you may be right that it will be a waste of time.

Never · 05-21-2019, 08:56 PM

Quote:

Originally Posted by Colox

I got this quite noticeable noise coming through my mic cable, though it is an XLR connection (with 48V fantom). It's like a low level static noise, together with what sounds like a highpass-filtered ground hum, which phases and fluctuates all the time.

But if I touch the casing of my soundcard, or just the metal casing of the XLR connector, then the noise slowly disappears (to at least 80%) over a 2-3 second fade out. I gotta touch the metal parts though. If I let go, boom the noise is back instantly.

I've made sure that the cable doesn't run close to any transformers, powercables, screens, Fluorescent lamps of any kind etc. And my soundcard is hooked up to the powergrid through a grounded outlet.

What is causing this BS?
Thx

@Colox - When you have a recording with the noise present, does there appear to be any (even minute) DC offset at all? It just seems like you could benefit from routing Mic>Preamp>DI Box>Sound Card....of course if you are pluggin directly into your sound card/interface...I guess that won't work. If it were me, (I do not like running my mic direct) I would find an old mixer or preamp and plug the mic into it, then if I still had the noise problem, I would get a piece of single conductor wire and link the chassis ground of the mixer to the chassis ground of the PC. Do you get any ground type noise when you plugin a guitar amp? Like maybe your outlets have an earth ground, but maybe the pin runs to the box, but the electrician did not drive the earth ground spike....this can be fixed easily. (Please consult electrician when dealing with AC.)Also....are you in a basement.....if so get a dehumidifier, and keep your guitars upstairs so they do not get dried out. (Simply a suggestion)

Alternately, I used to be a computer tech, and what I have found over the years, is that, while ASIO4ALL will let you use a generic sound interface, it cannot fix it's hardware issues, lol. See if your sound card has an 'FCC approved' (Or location equivalent)stamp or sticker. The FCC approval in my experience goes a long way to eliminating hum and line noise and HDD noise.

-Never