60Hz Hurts!

[TedP]

I have a constant 60Hz hum while recording from the radio.
Here’s the setup I use to record from the radio:

1] Shielded cable from stereo’s 1/8” headphone jack to Turtle Beach Santa Cruz card Line In jack. Stereo has no line out.

2] Santa Cruz Card is in Dell Dimension 8200 system.

3] Signal is picked up and recorded by software as mp3 file. Software is Total Recorder by Highcriteria.com. Excellent software – straightforward with many features, no junky popups, ads, etc. It has a great timer that performs unattended recording perfectly.

The source of the hum seems to be the line in jack. I know this because CDs and mp3 files created elsewhere play perfectly through the same system, with no hum. The Santa Cruz card has a software interface with a “mixer” that allows selection of signal. Toggle on the linein – 60Hz hum. Toggle off – no hum. This is the case regardless of whether the sound system is in use. Toggled on, there is a constant hum over the expected silence.

Strength of the hum varies if I jiggle the cable in the line in jack. It never disappears, though.

Otherwise the arrangement to record from the radio works perfectly.

Is there a way to get the sound signal into the computer other than the line in jack?

If I am constrained by the line in input into the system, is there a way to make a connection that is better than the 1/8 jack?

Alternatively, is there a way to cut out the signal at exactly 60Hz? I am recording talk radio, so sound quality is not super-important. Is there some type of digital equalizer that will cut out the signal exactly at 60Hz but leaves the rest of the signal intact?

Thank you

 

[moskus]

Sounds like there's something wrong with your line in... I would look for a new soundcard. Or try a new cable.

How do you know it's excatly 60 Hz? If it is, maybe you could use an EQ to remove it?

 

[esactun]

Are you near any flourescent light fixtures? Those can cause nasty hums and buzzes.

If your problem is purely at 60hz, it could probably be EQ'd out fairly easily. Sometimes, though, the sound has harmonic content, meaning that it has overtones at other frequencies that are mathematically related to 60hz, the fundamental note. In those cases, you either have to kill the hum at it's source (the preferred option) or use something like Cool Edit's sampling noise reduction.

Hope this helps!

 

[Slackmaster2K]

Try plugging the radio in backwards. (seriously)

Slackmaster 2000

 

[TexRoadkill]

Make sure the radio and computer are plugged into the same outlet. If that doesnt work lift the grounds on them.

 

[RWhite]

Check to see if when you turn off your monitor, the hum goes away.

 

[Ethan Winer]

Ted,

> I have a constant 60Hz hum while recording from the radio. <

Buy an Ebtech Hum Eliminator. It is meant to solve exactly this problem.

--Ethan

 

[hrn]

some suggestions, saw that some of them were mentioned before. 60 Hz tells it's a ground problem probably directly or transmitted from another electrical source. Try this:


* ground problem in cable or in radio connectors

* flourescent light fixtures near to cable

* computer monitor near to cable

* tv monitor near to cable

* power supply near to cable

* try to mute signals not used in the computers sound mixer

* plugging the radio in backwards

* try to put some tape over the plugs ground contacts (disable ground)

* constant tone in your head when listening to radio, check the head

These problems are really annoying, especially if you have the last one :]

Hans
www.hagen.nu

 

[haburton]

I use that same setup but I do not have that problem. I have the TB Santa Cruz card and it is NOT prone to hum. What you didn't say though, was where on the radio are you picking up the signal? Are you using a headphone jack, clipping across a speaker, what? What kind of radio is it? I have used that exact setup using a Sony Walkman to record many an old tape and off-the-air program with not a trace of hum.

Here are some things to think about:

1. The Line input is Stereo. Are you feeding it a stereo signal? If you are coming off the speaker, you definately are not.

2. Do they both plug into the wall? If so, they should be powered from the same wall plug. If the radio is not grounded, I agree with the previous suggestion, remove the radio plug, turn it over and plug it back in. That actually helps a lot in ungrounded systems.

3. Do you get hum in both left and rignt channels or just one? If you are clipped across a speaker or something, the unused channel is still recording an open circuit; lots of hum.

4. Have you tried new cables, preferrably NOT from Radio Shack? While I don't RS bash, some of their cables are not of the best quality. I find that in some cases, they don't carry good grounds through on stereo cables. Use their more expensive ones and they should be alright.

5. Do you have any adapters in use? Same reason.

The best interface is if both have a line level. If you radio has a "tape out" or "line out" jack, that is what I'd use.

If you have to go across a speaker or earphone jack, try out a direct box. They don't have to be expensive for this application, but they will provide isolation and level/impedance conversion and will generally improve your recording.

Check the little things first. I'd try a lot before i chucked my TB SC card.

Good luck.