One of my speakers developed a loud hum on the powered subwoofer side of the speaker. When I first noticed the hum I could tap on the amp and it would go away. But after turning my hometheatre amp on it would come back. This went on for about 15 minutes. Now the hum is gone but there is no sound coming out of the sub. The fuse is ok on the amp but I don't hear the speaker "click" on like the right speaker does. The front LED is still on so I know that it is getting power. Is my amp fried? Or is it the sub speaker itself? I also tried using both the "rca" inputs and the "speaker in" inputs and nothing changed. Polk Audio wants $200 for a new replacement amp. The rest of the speaker works fine. Any help or suggestions would greatly be appreciated.
- If you need clarification, ask it in the comment box above.
- Better answers use proper spelling and grammar.
- Provide details, support with references or personal experience.
Tell us some more! Your answer needs to include more details to help people.You can't post answers that contain an email address.Please enter a valid email address.The email address entered is already associated to an account.Login to postPlease use English characters only.
Tip: The max point reward for answering a question is 15.
I would check the caps on the power supply. They are rather large electrolytic capacitors that will look like they burst and/or leaking. When these die, the caps ground and the sub will make a loud buzzing sound. If you are handy with a soldering iron you can replace them yourself. Replace them with the same voltage or a little bigger and same with the size.
If the cap. says 16v 4700pF on it, for example, a 20v 5300pF or a 16v 6200mF cap. will work for this application.
Switch on your amp, keep its volue down to extreme low, and listen if there is still hum through the left channel or not. If still there is hum, the left side power amplifier section inside the amp;ifier is faulty. If htere is no hum at this state, hum enters thorugh the audio input terminal, and the input wires must be checked for open sheild connection. OK.
The hum (50 or 60 Hz) is caused by the AC power getting into the entry point of the amplifier. Either the filtering capacitors from the powersource of the speakers have dried up - replace them - or there is a short in the cables. There is another possibility: if you have kicked the subwoofer box its transformer might have slipped from its fixings and now is touching the subwoofer speaker frame.
The only way to find which is to open the cases.
Most probably it's an internal problem with their power supply (a capacitor with broken soldering). It can be quite easily repaired by a person knowing which side of a soldering iron to grip ;) If you have a friend that's familiar with electronics, you can ask to take a look. If you don't, the repair shop will most probably want a flat charge, which will not be feasible.