Loud noise from subwoofer on standby or while playing music
My Teac CD-X8 worked great until a week ago when I turned the subwoofer on and heard a very loud hum, which continued even when I put on a CD. Since then, the noise is there all the time, sometimes it gets even louder - like an airplane; makes it impossible to use the system. Is there anything I can do short of throwing it out?
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It sounds like you are describing an earth loop problem. I won't go into detail in this post, but try an isolation test first. disconnect everything from the reciever except the sub and try connecting say a BATTERY powered mp3 player or cd player to minimise connections to the electrical mains earth. you could also isolate things by taking your sub to a friend's house and trying it on their system. If it is an earth loop use a process of elimination to find out which two pieces of equipment causes the earth loop. then apply filtering. you can buy earth loop isolation transformers for about AU$26 and I've used one on my sub myself. Theyhave RCA (phono)plugs on each end and they connect inline with the signal cable to the sub amp.
as for the thumping sound it might be the speaker protection circuitry cutting off the amp to protect the subwoofer speaker from damaged. This might be triggered if the earth loop sound is causing the sub amp to overload and clip.
Failing this there might be a dried out overheated electro capacitor in the amp circuit causing the hum. Hav a chat to your local electronics person, who should be able to spot it! Hope this puts you on the right track Happy Hunting!
Neither the amp or the sub have grounded power cords.
I have discovered the ML Dynamo takes about 30 minutes to switch to
standby in auto mode.
With speaker level inputs connected to the Onkyo
A807 amp, both units powered from the same wall outlet, Dynamo sub on
Auto, the sub hums for about half an hour after the Onkyo is switched
off, then the sub goes quiet. Not so good.
I connected a bonding wire between the two units on 3_7_09. If I smoked
some old audio gear I could just look at that as an opportunity, right?
Works fine. Now I have the ML powered from the wall and working
A few more questions-
Does the sub hum without anything plugged into it except for power? If it makes a real loud hum almost a squeal then I think the rca cable between the receiver and the sub is dead shorted and needs to be replaced. If it's more of a low level hum, then it's a ground hum caused by many things, ie........the receiver and the sub being on different power circuits in the house.......sometimes diconnecting the cable tv feed as it enters the room while the sub is connected and humming to see if it stops........the easy fix sometimes is using a 3 to 2 prong ac adapter but lifting the ground on such a powerful amp could be a fire hazard.
or go to this site for contact details
or you can
e-mail to email@example.com and request a manual,
this link will let you get the manual online
only slight problem is this download will cost you $11.99, should be free from teac direct.
Hope this helps