line noise

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catpuke

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I have an unbearable amount of line noise

sometimes i can get rid of it by fidgeting with the connection of the mic to the cable

sometimes i can hear a radio station in the signal interference

please help! (anyone who's had similar experiences)
 
mic---nady spc-10 condenser into tube MP studio preamp into e-mu 1212m
 
Try a different cable. (make sure it is a proper mic cable, not xlr to 1/4 inch)
Are you using a balanced cable beween the preamp and the sound card?
If it isn't one of these, you need to get the mic fixed.
 
It's a balanced xlr to xlr from mic to preamp, and (I presume unbalanced) xlr to 1/4" from preamp to e-mu 1212m

both cables say low noise

everything is brand new--mic, cables, preamp, and emu 1212m
 
First, try a different mic cable. Even new stuff comes broken. If you still have the problem, it's probably in the XLR connector of your mic, since you can fix it by twiddling there. It sounds like you have an intermittent open circuit. If the mic is new and under warranty, get a new one. If not, take it apart and inspect and resolder the wires to the connector.

I've got six cats - three are longhairs. Pukey hairballs everywhere.
 
now have all balanced cables and tried a new mic, same thing

--about 30 seconds after I turn on the preamp i get a loud steady hum
--if I touch the mic the hum wavers a bit, but remains very loud, and sometimes receives a radio station
--it seems to me to be akin to old-fashioned television reception (when a person touching the antenna affected the signal)

does this sound like a ground loop?
if so, how do I solve the problem? (the outlet is grounded)
could it be something else?
anyone with similar experiences?
 
It sounds like you've changed the mic. Did you change the mic cable? It's unclear from your post. Did you change the cable from the preamp to the sound card? Sounds like you have.

If so, and the problem persists, this leaves the preamp and the sound card. You say these are new also. Have you used a different preamp? If not, you need to try a different one. The one you have probably didn't have to pass very stringent quality control. :)

Your soundcard has two analog inputs: does it make any difference which one you plug in to?
 
Is this a new problem?

Is the pre-amp and mixer grounded? Better yet...is everything grounded? Us home recordist's can usually get by making sure that all the factory power cords are servicable and the power source is up to code.

Is your electric service to the equipment clean or are you using old extension cords. Sound a bit like you might have a floating ground if your mic cable is good, connections are good, radio noise changes when you move the cable around (you're moving the antenna). The shield in the cable should be grounded through the amp and mixer.

Sorry about all the questions but these are some thing that might help us to figure out what's going on.
 
catpuke said:
now have all balanced cables and tried a new mic, same thing

--about 30 seconds after I turn on the preamp i get a loud steady hum
--if I touch the mic the hum wavers a bit, but remains very loud, and sometimes receives a radio station
--it seems to me to be akin to old-fashioned television reception (when a person touching the antenna affected the signal)

does this sound like a ground loop?
if so, how do I solve the problem? (the outlet is grounded)
could it be something else?
anyone with similar experiences?
Click to expand...
Sounds to me like the tube pre(just guessing here)I had a hell of a time with pickin' up a Mexican radio station thru my guitar amp(tube head+crappy house wiring)The noise gate on my rack gear took care of that.If all your cables are all good,try a different outlet and/or a different pre(if you can),like had been said.Either something's not grounded proper in your system or your house wiring(or the pre's screwed).That's my guess anyway. :confused: ...good luck.
 
punkin,

not new, it's been this way since i hooked it all up, a couple months ago

the preamp is plugged into the same power strip as the computer

the emu1212m serves as a mixer (in the computer)

the house is a mess electrically (bought it from a "home improvement" guy)
----there's dead outlets and switches, some are grounded, some aren't
----the outlet the computer is plugged into is grounded to a water pipe

any suggestions? any easy ways to fix the problem without moving or rewiring the house?
 
catpuke said:
the preamp is plugged into the same power strip as the computer

the house is a mess electrically (bought it from a "home improvement" guy)
----there's dead outlets and switches, some are grounded, some aren't
----the outlet the computer is plugged into is grounded to a water pipe

any suggestions? any easy ways to fix the problem without moving or rewiring the house?
Click to expand...
Yep...same story here about the house wiring.You can try buying one of those thick outdoor type extention cords(25 ft. or so),plug your strip into it and try all of your wall sockets.See if the noise goes away.I have all my stuff(2 puters,3 monitors,a printer,telephone,lamp,ect.)plugged in that way(25 ft. I think)with no problems.
 
Last edited:
There's a fundamental problem here and I think your biggest concern should be safety. If there's no ground at the outlet, you stand a good chance of developing electrical differences of potential between the various devices. When you touch them or connect cables between them you start to close circuits and create current which makes noise and can be dangerous.

If you're familiar with how to use a volt/ohm meter, I would recommend reading up on a good DIY electrical book and start doing some troubleshooting or, better yet, contact an electrical contractor to evaluate the situation. The repairs could be simple...it could get messy. It's hard to say.

Best of luck to you.
 
still no solution to line noise problem

refresher info--

i have a nady spc-10 condenser----->low noise balanced mic cable (xlr to xlr)----->ART tube MPstudio pre-amp----->low noise balanced mic cable (xlr to 1/4")----->e-mu 1212m

e-mu said to disconnect everything and reconnect one by one till the problem is recreated (the last connected object is the offending one)----everything was fine till i reconnected the nady spc-10 mic to its cable

nady said it must be an unshielded cable

anyone out there who can make sense of this problem?
 
do you have any other mics you can try with that cable?
 
no, i plan on buying one this week or next, hate to do that if it's not going to solve the problem, but guess i don't have any choice

i noticed in a musicians' friend catalog that it separates the mics into performance and recording--anyone know what the difference is?

the nady spc-10 is under performance, not recording
 
crazydoc said:
First, try a different mic cable. Even new stuff comes broken. If you still have the problem, it's probably in the XLR connector of your mic, since you can fix it by twiddling there. It sounds like you have an intermittent open circuit. If the mic is new and under warranty, get a new one. If not, take it apart and inspect and resolder the wires to the connector.

I've got six cats - three are longhairs. Pukey hairballs everywhere.
Click to expand...
I'll still go with this, since it's not clear if you ever got a different mic (xlr to xlr) cable. If you did, and the problem persists, then it's likely in the mic's xlr connector, as you said in your first post that you can get rid of the problem by fiddling with the cable to mic connection. These are the first things to check, and it doesn't seem like you have.

I don't know what they mean by "performance" mic, except that it's an end-address mic to be held in a Shure type mic clip or hand held. Also, it has a "tight cardioid pattern" which would help in feedback rejection. There's no reason you can't use it for recording - look at the Shure SM57 and 58 (and many others) that are used for both performance and recording.
 
crazydoc--thx

it's hard to differentiate between professional advice and internet know-it-alls

bought a shure sm58, the problem disappeared completely

thx alot crazydoc, i'll recommend you for an extra dollar in your pay envelope this week
 
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