Buzzing sound during recording

[buzz11]

Basically when there's no music playing, before songs start, after songs end, or as the music fades at the end of a song when the music is barely audible, I can hear a very distinct buzzing sound. I don't have to be recording. Even if I just set it to monitor, the buzzing will start. I just recorded a few songs for the first time so I can't tell you if the buzzing will occur right in the middle of a song because the songs I recorded don't have a quiet part in the middle. But so far I can't hear any buzzing at any other time during a song.

I'm recording old records using a pretty powerful receiver. I have a splitter connected to output jacks on my receiver and a 1/8 stereo plug connected to the audio input on my Macbook Pro running OS 10.5.8

Any clues?

Thanks.

[billw58]

Try running the MacBook on battery only. The splitter could also be an issue.

-- Bill

[kozikowski]

And if that works, try plugging your MacBook in backwards. That is, flip the power supply plug around in the wall. Mine isn't polarized and yours probably isn't, either.

It is a little unusual for hum to happen in these systems -- you really have to work at it.

You said you have a "receiver" connected to the system. Is it on an external FM antenna or other FM antenna system? Try unplugging the antenna and run the system again.

Do you love dark, sensual dimmers in your house? Nothing creates tons of power line garbage --buzz and trash -- than dimmers. Dimmers work by switching very high power on and off very rapidly 120 times a second. Surprise. That makes trash at all the harmonics 240, 480, etc.

Let us know. There's a bunch of things you can do to help.

Koz

[buzz11]

Unplugging my Macbook power supply cord did the trick. Such a simple thing and I was trying everything else.

Thanks for your all your advice.

[kozikowski]

Yes, but you can't run on batteries forever. Did any of the other tricks work?

Koz

[buzz11]

I forgot to mention:

I tried flipping the Macbook plug but no result. I actually grounded and polarized my outlet myself so I didn't think I would have a problem here. I know it is grounded and polarized because I tested it with a surge protector that has light indicators. But currently I only have a polarizing power bar connected to that outlet. My turntable was plugged into the receiver and the receiver and Macbook power cord were both plugged into the same power bar. Just to test, I tried plugging my stereo into a polarized surge protector that is plugged into a different outlet that is not grounded. Now even with the Macbook power cord plugged in, no buzzing. But the funny thing is now I can't get the buzzing to start up again even when I plug both into the same power bar.

For my receiver I don't have any antenna attached and I don't use a dimmer either. I do live in an old apartment though. One that was built before polarizing outlets were standard.

[kozikowski]

We had one room with technical equipment in it in the old building. Whenever we got complaints of hum and buzz, we could clear it by replugging the equipment into the wall. Nobody ever found anything wrong with the socket or the plugs, it just worked -- then we moved.

Koz

[buzz11]

I did some experimenting and here's what I found.

Plugging the stereo and Macbook Pro power cords into different surge protectors essentially eliminated the buzzing. Don't know if it matters that the surge protectors are plugged into different outlets but in my case they are plugged into different outlets.

Apparently both power cords can be plugged into the same surge protector, just make sure it's a good surge protector. When I plugged both power cords into a different surge protector, that's not plugged into a grounded outlet, the hum was essentially eliminated.

I have two Belkin surge protectors. The more expensive one (only $14) is only 6 months old and the cheaper one (maybe $7) that gave me the problems is about 3 years old. I thought the older one was only a power bar but turns out it is a surge protector. Both surge protectors have lights to indicate grounding but only the newer one features a light to indicate polarization. It was always my understanding that all surge protectors are polarizing but for whatever reason, one surge protector buzzes and the other does not. Interesting to note that the cheaper one is heavier with an all metal body and the more expensive one is lighter with an all plastic body.

For the most part the buzzing was eliminated since I could only hear very faint buzzing when I turned my laptop volume up to the max, which is like turning your stereo volume to the max which will of course create some buzzing. But if I still wanted absolute silence, even with the volume up to the max, then I still had to unplug the Macbook power cord.

[kozikowski]

Now you know the natural limitation of "hifi" sound cables. Because of the "ground," green, or safety prong on many power cables, the outer connection on your RCA cables (or any sound cable with a shield connection) is the same wire as the third prong at your washing machine, your garbage disposal, and the belt sander out in the garage. Your whole house becomes a part of your audio connection.

If you have protected power strips, then you also have a partial connection between the Neutral and the Hot -- the other two pins in the power plug. Depending on how they manufactured the strips, the connection may be different and cause all sorts of sound problems.

Broadcast and Studio sound cables and equipment have three wires, not two and don't use the power line as part of the sound signal.

What happens if you take all the fancy-pants power strips out of the circuit, plug one plain strip into the wall and plug everything into that?

Koz