Hum from woofer.

[Michael r]

My bass active woofer hums. I'ts a Yamaha YST-SW60 - 70WATTS - the hum level can be raised and lowered using the vol. control on the unit. The amp is a Yamaha DSP-A780. Removing the input to the woofer eliminates the hum completely. My rig is about 15yrs old and was ok up to about 2months ago - did'nt do anything to bring it on as far as I know. What areas should I start lookin? Many thanks Michael r

 

[j_garcia]

Check the first thread in this forum regarding hum; that would be the first place to start with things to check. If you've plugged anything new into the system it could potentially cause this. A loose or damaged cable can cause this as well, maybe you could try another cable to the sub just to make sure that isn't it?

 

[Rob Babcock]

A hum is almost always caused by a grounding problem. You cable TV line is the most likely culprit, but it could be any component. I'd suggest you first disconnect the cable TV (assuming it's connected) and see if that does it. If not, disconnect each component one at a time until the hum is gone.

If it's the CATV, there are inexpensive devices that will fix the problem. If it's the grounding of another component, you may be able to use a "cheater" plug, although some electricians will frown upon it.

If it's none of the above you could have a problem with the woofer. Not much you can do to service it yourself- that will require an expert. Still it's best to rule out the obvious stuff first.

 

[pelvis70]

My cats wrecked my sub cable behind my entertainment system and it caused the same problem you are experiencing, try a new cable

 

[Michael r]

Hum

A hum is almost always caused by a grounding problem. You cable TV line is the most likely culprit, but it could be any component. I'd suggest you first disconnect the cable TV (assuming it's connected) and see if that does it. If not, disconnect each component one at a time until the hum is gone.

If it's the CATV, there are inexpensive devices that will fix the problem. If it's the grounding of another component, you may be able to use a "cheater" plug, although some electricians will frown upon it.

If it's none of the above you could have a problem with the woofer. Not much you can do to service it yourself- that will require an expert. Still it's best to rule out the obvious stuff first.

Many thanks for quick response. Have taken easy way out and switched off everything from the mains except the sub-woofer itself. Interesting in that the hum stayed on - and still adjustable with using the volume control. However when I pulled out the banana plug (input plug - I'm sure it has a more technical name than that!) which comes from the now totally dead Yamaha audio amp -- the hum cleared instantly - not a trace. Reinserting the input plug causes the hum to re-appear as bad as ever - permeates the whole room with a most disconcerting throbbing noise -- wifey not liking!. Will change the plug (might be faulty?) and let you know. Many thanks aagain Michael r.

 

[Michael r]

Hum

Many thanks for quick response. Have taken easy way out and switched off everything from the mains except the sub-woofer itself. Interesting in that the hum stayed on - and still adjustable with using the volume control. However when I pulled out the banana plug (input plug - I'm sure it has a more technical name than that!) which comes from the now totally dead Yamaha audio amp -- the hum cleared instantly - not a trace. Reinserting the input plug causes the hum to re-appear as bad as ever - permeates the whole room with a most disconcerting throbbing noise -- wifey not liking!. Will change the plug (might be faulty?) and let you know. Many thanks again Michael r.

New day. Replaced the plug going into the sub-woofer powered amp -- hum 90% reduced but not eliminated totally -- only apparent when vol. turned up more than halfway - maybe I can live with that! Any ideas for complete success? Many thanks anyway, Michael r. ps Old plug looked perfect -- just goes to show -- all is not as it appears -- be warned!

 

[mtrycrafts]

New day. Replaced the plug going into the sub-woofer powered amp -- hum 90% reduced but not eliminated totally -- only apparent when vol. turned up more than halfway - maybe I can live with that! Any ideas for complete success? Many thanks anyway, Michael r. ps Old plug looked perfect -- just goes to show -- all is not as it appears -- be warned!

See what happens when you unplug the TV cable to the system, directly or even indirectly through another component that is connected to the system.