My BK XXLS400 developed a hum…

[Raymond Lin]

No idea what happened, watching a movie and after a loud section in a movie I started hearing a weird hum from the sub, I’ve disconnected all the wires and it is still present.

Doing a bit of reading it sounds like it could be either a transformer hum or a dead capacitor or solder joint…

I got it like 15+ years ago so way out of warranty and honestly with its weight, not sure how I could send it back for repair. I have emailed BK to see what they say anyhow.

What would you guys do? And anyone have experience of this here?

 

[Raymond Lin]

If it was broke, out of warranty, and cost too much for a repair. I'd try and find the diagrams and strip it apart. Probably only a small board anyway, so probably easy to work out?

Or find a local electronics technician, local audio shop?

I guess calling a local place can’t hurt. If it’s a capacitor then it’ll be cheap, if it’s a new transformer then I might have to get a new one…

 

[Raymond Lin]

I recall BK charge £75 for repair that includes shipping

Don't need to send whole sub back just plate amp. Although it just happened to fail on loud part so I'd probably want the driver tested maybe you blew the driver?

I don’t think so as it wasn’t that loud as I was watching a film at 11pm.

I also noticed that it hasn’t sounded the same for a while, I thought it was the new Denon I got last year but it had felt off since. But the hum is a new development.

I will call BK on Monday in person to see what they say first I think. I think anyhing under £250 would be justifiable to repair it vs the cost of a new one.

 

[Raymond Lin]

BK got back to me, sent me instruction of how to take it out, pretty easy.

I can't see any burnt caps.

Although I notice the sub isn't doing anything, I unplugged the Anti-mode and ran just the IC cable to the sub did a Audessy test...i thought i felt the sub move but when watching a movie I could not feel any low frequency...

 

[Raymond Lin]

Packing it up is a challenge I must say!

 

[Raymond Lin]

Update.

"A faulty high voltage power supply capacitor would have been the cause of the humming, but the amplifier hardly had any signal output and that's why you lost bass, this is caused by the capacitors on the low voltage supply. Both sets have been replaced and the amplifier is working, it will be passed onto another engineer to check the first engineers work and he will final test it."

Total cost £55 which includes VAT and shipping!

 

[Raymond Lin]

Do you have instructions/details on this?

My xxls is also not working properly (kind of constant buzz)

Particularly how to get it apart?

This was the link they sent me

Opening an XLS200-DF

How to open an XLS200-DF

youtu.be

When detaching the cable from the PCB to the speaker, mark which one is positive and negative so you know when you put it back together.

 

[Raymond Lin]

I'm pretty sure I don't have that cable anywhere he used to pull it open

Oh, that’s the low pass cable.

If you loosen the screws and turn it so the amp is facing down, if you lift the wood cabinet it could just fall right out because the amp part weights about 6kg. The only thing holding it in place is the gasket which might act like glue but it really isn’t on mine. A bit of hair dryer and then pull from the cable it came away really easily. Just make sure you don’t miss a screw.

if you can’t, one of those orange Lego brick splitter thing could work.