Had my BA subwoofer for 4 years and it had a terrible coil whine squeal from day one.
I RMA'd it twice, but both times it came back (after a 6-8 weeks return time) and had the exact same problem.
Said they "swapped the amplifier module". As it didnt help, personally I feel more convinced its the PSU module.
Its a coil whine tone, maybe around 4.5Khz. Its terrible agonizing, when worst I hear it clearly 4-5 m from the Sub (because sits in corner).
It wines without PCA input. It whines in both active mode and stand by (inactive) mode, though changes a bit in frequency and often gets noticeably higher when in stand by!
I whines if I move it to a completely other room in the house. Whine makes a weird "squeak squeak squeaaiik" and then dies, when power is pulled.
I opened the sub, not being able to exactly pin point the source. I also didnt see any bulged caps, everything looks normal and smells new.
Fun fact; Im pretty sure the sound dropped dramatically when sub was upside down, being opened up. I have basic knowledge and repair skills like changing dead caps.
Question is: Will I be good with "drowning" the coils (I see at least 2) with eg. hot glue? Or what to do?
Thanks!!
Diagram (I THINK): Box
I RMA'd it twice, but both times it came back (after a 6-8 weeks return time) and had the exact same problem.
Said they "swapped the amplifier module". As it didnt help, personally I feel more convinced its the PSU module.
Its a coil whine tone, maybe around 4.5Khz. Its terrible agonizing, when worst I hear it clearly 4-5 m from the Sub (because sits in corner).
It wines without PCA input. It whines in both active mode and stand by (inactive) mode, though changes a bit in frequency and often gets noticeably higher when in stand by!
I whines if I move it to a completely other room in the house. Whine makes a weird "squeak squeak squeaaiik" and then dies, when power is pulled.
I opened the sub, not being able to exactly pin point the source. I also didnt see any bulged caps, everything looks normal and smells new.
Fun fact; Im pretty sure the sound dropped dramatically when sub was upside down, being opened up. I have basic knowledge and repair skills like changing dead caps.
Question is: Will I be good with "drowning" the coils (I see at least 2) with eg. hot glue? Or what to do?
Thanks!!
Diagram (I THINK): Box
I'd use silicone RTV that is safe for electronic work. Don't use regular bathroom caulk as it will corrode everything it touches.
First find the component that makes the noise. I have read that a flexible tube can be used to probe different components. Put one end to your ear and the other at the circuit board.
Thanks. The culprit is the ferrit dressed in yellow in this picture. Im 90% sure as if I press point A the noise almost goes away and if I press points B there's a small difference but not a lot.
Im not exactly sure what the purpose of this part is. Noise reduction? Im convinced the board is the part that relays the subwoofer into standby mode after some minutes when there's no input.
The ferrit looks to already be covered in some compound, and rapped in a yellow piece of paper or tape.
Whats your best suggestion?
I read about painting it with nail polish as I only have general house hold remedies, I don't have any professional RTV silicone or conformal coating.
Attachments
A is the transformer.
I am not sure if it can be silenced. I would not use nail polish, as unknown solvents could compromise the galvanic isolation between the primary and secondary side. Old school 50/60 Hz transformers can be vacuum impregnated when they buzz (search for 'transformer buzz'), though I do not know whether the same can safely be done to smps transformers. Motor shops might have the equipment for vacuum impregnating. Dipping a transformer in varnish is also possible, but the varnish will not reach all pores so it works less well. It might be all you need though.
I am not sure if it can be silenced. I would not use nail polish, as unknown solvents could compromise the galvanic isolation between the primary and secondary side. Old school 50/60 Hz transformers can be vacuum impregnated when they buzz (search for 'transformer buzz'), though I do not know whether the same can safely be done to smps transformers. Motor shops might have the equipment for vacuum impregnating. Dipping a transformer in varnish is also possible, but the varnish will not reach all pores so it works less well. It might be all you need though.
Last edited:
I took a risky decision and will let you know how it worked out;
I had some red varnish for light bulbs lying around. I coated the transformer in a thick layer and let the remains drip off. Its currently hardening, if that didn't help anything Im gonna cover it completely in hot glue.
If that doesnt work Ill decide between soldering out the transformer and getting a replacement - or simply give up on the sub and replace the unit.
I was in a tight spot money wise at the time of purchase and didn't realize how crappy components its apparently made up of. 🙁
To anyone interested. I lacquered the transformer with red varnish (made specifically for coloring light bulbs - not exactly this purpose but it was what I had lying around).
After letting it harden for 24 hours I covered the little transformer and most surrounding area with hot glue and reassembled the sub.
So far it's dead silent and works like before. Thanks for your input.
NB Sometimes you just gotta work with what ever you have at hand IMO. Suffering from tinnitus it was either creating a usable solution removing the squeak, or trashing the sub and buy another. Just saved me 150-200£/€.
After letting it harden for 24 hours I covered the little transformer and most surrounding area with hot glue and reassembled the sub.
So far it's dead silent and works like before. Thanks for your input.
NB Sometimes you just gotta work with what ever you have at hand IMO. Suffering from tinnitus it was either creating a usable solution removing the squeak, or trashing the sub and buy another. Just saved me 150-200£/€.