Hum, Hum , Hum

Analoghead

Just Joined & need help. PSW12 HUM. What to do?

dudeinaroom

A search for the problem using the search feature here in the forums. It has been covers many times over the years. It is most likely the cable going to the sub. Disconnect it at the sub and see if it goes away, also keep the cable away from power cords.
Welcome to the forums

wingnut4772

Yep. Power Cord or cable crossing somewhere. Try some cable management first and welcome.:)

Yashu

Make sure you plug the sub in the same outlet as the rest of your stuff. That is what caused hum with my sub a while back when I had one.

TN_Polk_Lover

First of all, welcome to Club Polk. Does the PSW12 have a 3 prong plug? Does your receiver have a 3 prong plug? If so, you probably have what is called a "ground loop" going on.

Here is an excellent article that describes this, but below I've kindof paraphrased in my own words what I learned and how I fixed my problem.

http://www.audioholics.com/tweaks/connecting-your-system/ground-loops-eliminating-system-hum-and-buzz/


Here are 2 different scenarios:

Scenario1: You have a receiver with a 3 prong plug that you were already using and had no hum problem until you added the PSW12 which also has a 3 prong plug. Most likely, you have the subwoofer plugged into a different outlet than the receiver because you have the subwoofer located in a different spot in the room. The ground "potential" is different between the 2 pieces of equipment. Since the sheild of the subwoofer cable connects the 2 pieces of equipment together, then a small current flows from one piece to the other. Along the way, that current will pick up noise such as 60 cycle hum and also noise from light dimmers, flourescent lights, etc. that might be nearby or on the same circuit. Now, the best way to fix this? Some people "unground" one piece of equipment by using a "3 prong to 2 prong" cheater adapter. this is usually not recommended because it removes the protection from shock that the manufacturer built into the equipment. Some people use an isolation transformer to plug one piece of equipment into, although these are usually expensive.

Scenario 2 You have a receiver which may or may not have a 3 prong adapter. You have cable TV coax connection connected to you TV. The TV audio out is connected to your receiver with analog audio cables. You may also have compenent video cables going from your receiver to your TV. You have not had any hum until you added the new subwoofer which has a 3 prong plug. In this case, the ground loop is going from the subwoofer, through the sheild of the subwoofer cable to the receiver, through the shield of the audio and/or video cables to the TV and then through the shield of the TV Cable Coax cable back to where the cable TV is grounded where it comes into the house. The easiest way to cure this is to get an isolation transformer that goes in-line between your cable TV connection and you TV. The easiest way to test this is to unscrew the cable connection from the back of your TV and if the hum stops you know this is the problem.

Scenario 2 happened to me, except that it happened when I added an external amp to my setup. Actually, I had an external Yamaha power amp that did not have a 3 prong plug and upgraded to a Parasound amp that had a 3 prong plug. Immediately, I was getting noise / hum through my speakers when playing no music. If I played music, it would mask the noise, but with no music, the noise / hum was there.

I recognized the hum as 60 cycle hum, but there was some square wave noise mixed in there too. I had 2 torchiere lamps in the room that were the dimmable flourescent type. I turned them off and the "noise" went away, but the 60 cycle (sine wave) hum was still there. At first I thought I was going to have to get a power conditioner to plug everything into and I started researching that topic to decide the best one to buy. But, after about 2 days of that research, I just decided to google "ground loop hum" and that lead me to an article that immediately pointed to the Cable TV connection. I unscrewed the Cable connection and the hum stopped.

I found this company which sells such a device along with an excellent article explaining the problem. You can buy from them direct, but only by phone.

http://www.jensen-transformers.com/iso_vid.html
Look down the page for the product: Model VRD-1FF Cable TV RF Isolator.

Then I found this company in Texas which sells this product online and wound up buying one from them. It cured my problem completely.

http://www.cs1.net/cables/products/jensen_transformers/VRD-1FF.htm

Again, welcome to Club Polk. I hope this helps point you in the right direction to cure your problem. You'll find this forum to be very friendly with lots of helpful people.