Buzzing subwoofer. Any way to bypass

dori2o

I have a stereo which has a subwoofer and 2 speakers.

The sub is buzzing/humming.

You can even hear it when using headphones.

The sub is also the main power source with the stereo connected to it using a 9 pin mini DIN cable. The speakers also plug into the sub via RCA connectors.

Can anyone advise how to get rid of the hum or is the system knackered?

Is there any way to bypass the sub and power the stereo directly?

Any advice appreciated.

kwikbreaks

If it's a constant hum then it sounds like the smoothing capacitors in the PSU are past their sell-by date. This is the most likely problem as you hear the noise in your headphones.

How easy it is to fix depends more on your skill levels than anything else. The most likely job of replacing a smoothing capacitor isn't hard if you know what you are doing and pretty much impossible if you don't.

Oblivion

It's a long time since I've dabbled with hi-fi setups but I recall that another source of hum was when an earth loop had been created, often because each component had it's own mains plug. The cure I think was usually to simply disconnect the earth wire from all but one of the plugs.

You could try disconnecting the earth from the subwoofer's power plug and see if that makes a difference.

Heedtheadvice

Potential to blow yourself to oblivion.......
Do not disconnect the earth wire on plugs. They are there for safety reasons!! If it is an earth loop then there are other ways to stop then being a problem but beyond posting on here.

It is more likely to be the PSU fault as described already (get the system to an engineer to check it over) or hum pickup by audio cables running too close to power cables or power unit transformers. You can find that out easily by re-routing them or at least separating audio from mains ones.

dori2o

OK.

I'm revisiting this as I've tried several configurations,changed leads and wires, moved cables etc and it's still humming.

The stereo itself is great,the biggest problem being that it is powered via the sub, via an 8 pin plug which also carries the audio to the sub and the speakers are plugged into there via an RCA/Phono connection.

The stereo unit however does house the AUX IN which is 2 sets of phono connectors (2 red, 2 white) and 1 3.5mm input,so therefore a potential 3 external connections

Would there be any way of re-routing power direct to the stereo, and re-routing the signal out direct to speakers possibly through a small 12v amp? therefore cutting out the sub all together?

Ideally I'd like to be abletorun direct from this stereo without the sub, and integrate bluetooth/usb/30pin/SD card into the stereo with an adapter which would normally be used to add AUX signals in a car (hence the 12v amp) which would be housed within the casing on the top of one of the speakers and input the stereo to one set of the aux in Phono connectors with my Turntable being connected to the other.

This would allow me to play music via bluetooth from my ipod through PLEX, so I have access to everything on my PC/external HDD, plug in my ipod to use the digital radio, and prettymuch listen to everything I have in all formats, including tape via the 3.5mm connector from an old Sony walkman.

almillar

Model number(s) of your setup is bound to help anyone answer...

googler

Oblivion wrote: »

You could try disconnecting the earth from the subwoofer's power plug and see if that makes a difference.

Noooooo.......

The subwoofer is the only thing connected to earth, from the sound of it.

paddyrg

I take it you've tried unplugging everything and just turning up the sub woofer core unit with no inputs? Buzz? Smoothing capacitor almost certainly. No buzz? Reattach sources one at a time until you have a culprit.

The smoothing capacitor (which is most likely candidate) is going to be sitting in the box near the transformer and be like a stout cylinder. Good chance one if them will look a bit bloated on top, that'll be the starting place for fixing it up. Don't do this with the unit plugged in, obviously, and certainly don't go removing earth protection from any devices that have it.

tonyh66

paddyrg wrote: »

I take it you've tried unplugging everything and just turning up the sub woofer core unit with no inputs? Buzz? Smoothing capacitor almost certainly. No buzz? Reattach sources one at a time until you have a culprit.

The smoothing capacitor (which is most likely candidate) is going to be sitting in the box near the transformer and be like a stout cylinder. Good chance one if them will look a bit bloated on top, that'll be the starting place for fixing it up. Don't do this with the unit plugged in, obviously, and certainly don't go removing earth protection from any devices that have it.

and make sure all the capacitors are fully discharged before touching them.....

paddyrg

tonyh66 wrote: »

and make sure all the capacitors are fully discharged before touching them.....

Indeed. Unlikely to be carrying mains voltage, more likely on the kind side of the transformer and almost certainly will have a discharge resistor in combination (on a quality system?), but yes, a prudent rule of thumb ;-)