Audio Hum

[cie3]

Several months ago I posted a question regarding an annoying audio hum on another thread in this forum. At that time, I was advised to purchase a ground loop isolator from Radio Shack as a possible remedy to eradicate an audio hum that I was hearing as I was (then) trying to make a VHS copy from another VHS tape. I also made sure per the additional advice in that first post to use one surge protector and to ensure that all components were plugged in the surge protector.

Anyway, I still hear this hum so that is why I bought the ground loop gizmo from Radio Shack yesterday. See link--
http://www.radioshack.com/product.asp?catalog_name=ctlg&product_id=270-054

Now, however, I only need to go from VHS copy to DVD disc via my new Pioneer 420H from Costco vs. making another copy of a VHS cassette.

Yet, I still do hear this hum. The hum may be from the crappy speakers in my TV, or it could already be on the VHS copy that is the one I am using to make my DVDs. (I don't have access to that particular original tape.) The hum is less noticeable when I have copied other tapes to DVD disc but I am still hearing some of this noise.

I thought I would try to hook up my TV to my stereo and try this first to see if it's really coming from my TV ..but I am confused as to where to best connect the ground loop isolator now that there might be even more components in this mix. Where would I best use this device to it's best effect? I need a starting point...

Would I use this between the VHS machine and the DVD recorder or would I use it between the TV and the AV receiver? Or would I move it to wherever the noise is most noticeable? The instructions on the package are not helpful. I don't have cable, composite or S Video connections on my TV by the way. Please advise,

E

[Soopafresh]

Do commercial DVDs hum when you play them ?

Can you post a five second clip of audio here so we can analyze the sound ?

[cie3]

I don't think so regarding a commercial DVD..will test one again tonight.

Don't know that I would be able to post a clip..for sure I won't be able to do it from home. How do I do this? What software will I need?

[zleepy]

Hum can come from many places, within your system or from the out side.
Is an electical part in one or more of your component in your system transmitting the
hum (like a radio does) and your cable, VCR and/or recorder are/is acting as an antenna?
This can found by switching the audio cable from vcr to audio casette deck
or by switching the position of the VCR/DVD-Recorder with a DVD or audio player with its power off.
Use the process of elimination, ie move a cable one at a time & check for hum change
OR did the hum move with the change, etc

Check sources out side the system.
Is there a power cable inside the wall behind your system or under the floor?
Is the room next to where the power enters your home?

Check for bad electrical part.
Poor connections in the cable or solder joints can cause audio hum.
Is it inside the cable, VCR or DVDR causing the hum?
Listen for any audio difference between the left/right/front/etc channels
and reverse the left with the right channel cable.
Did the hum change channels?
Use process of logical elimination.

Sumation:
Is the hum from an external electrical source like a flourescent fixture on the ceiling downstairs?

Is the hum from an electronic source in your system?

Is the hum cause by a damaged cable?
Remember that bending metal wire back and forth will break like a paper clip or staple.

Do the cable connectors make solid contact?

Is it caused by a cold solder joint inside your VCR or DVDR gear?

Is it cause by poorly designed electronics inside your VCR, DVDR or TV?
Poor or loose grounds, or filter capacitors are too small, or badly designed transformer, etc.

TIP
For laying microphone cables, I use a cassette walkman on play+pause and check
the floor for noise, like a mine sweeper.