Hi all
I needed some help regarding my Kef Kube 2 subwoofer
It recently stopped working and I sent off the amplifier part of the subwoofer to Kef to see if they could repair it. They were very helpful but unfortunately they discovered that there was alot of damage/burnt out areas on the power board and recommended I buy a new amplifier part to install into the enclosure.
I wanted to know if anyone has had a similar problem with this particular subwoofer and managed to fix this problem?
I have attached images of the subwoofer and also images of what Kef sent to me of the PCB of the amplifier and power supply
If this isnt worth the hassle could someone recommend an amplifier/power supply I could buy cheaply enough to carry on using my subwoofer until I am ready to either buy the replacement amp or even buy a new subwoofer.
Thanks in advance
I needed some help regarding my Kef Kube 2 subwoofer
It recently stopped working and I sent off the amplifier part of the subwoofer to Kef to see if they could repair it. They were very helpful but unfortunately they discovered that there was alot of damage/burnt out areas on the power board and recommended I buy a new amplifier part to install into the enclosure.
I wanted to know if anyone has had a similar problem with this particular subwoofer and managed to fix this problem?
I have attached images of the subwoofer and also images of what Kef sent to me of the PCB of the amplifier and power supply
If this isnt worth the hassle could someone recommend an amplifier/power supply I could buy cheaply enough to carry on using my subwoofer until I am ready to either buy the replacement amp or even buy a new subwoofer.
Thanks in advance
Last edited:
Well unless you know a lot about switch mode power supplies and class d amps, I think it will be a very difficult task to repair it.
From pictures the fault seem to be located around the switching transistor in the SMPS. But as it failed, it could quite well have causes all sorts of trouble in the amp section and maybe the speaker unit.
First chect the resistance over the driver. depending on whethere it is a 4 or an 8 ohm unit, it will be something like 3.2 ohm or 6.4 ohm. Also try to press the diaphragm in and out to make sure the voice coil does nor rub. If you have a propor resistance and no rubbing the unit should be ok.
from other pictures (kef kube 2 repair | AVForums) it looks as there is a separate pcb for the preamp and filter section.
You'll need to find out what the input wires are and what voltages are needed.
In stead of trying to repair the PSU and amp, I would go for changing these to something like this:
IRS2092 CLASS D Audio Power Amplifier AMP Kit 200W MONO Assembled Board UK | eBay
and
500W amplifier switching power supply board dual-voltage PSU +/-55V L164-11 | eBay
If the driver is a 4 ohm unit, chose PSU with +-40cd, if it is a 8 ohm unit chose 55 Vdc, both giving some like 200 Watt as output.
Be very carefull witht the SMPS PSU, we are talking about very high voltages, which can kill you!! So make sure you know what you are doing
From pictures the fault seem to be located around the switching transistor in the SMPS. But as it failed, it could quite well have causes all sorts of trouble in the amp section and maybe the speaker unit.
First chect the resistance over the driver. depending on whethere it is a 4 or an 8 ohm unit, it will be something like 3.2 ohm or 6.4 ohm. Also try to press the diaphragm in and out to make sure the voice coil does nor rub. If you have a propor resistance and no rubbing the unit should be ok.
from other pictures (kef kube 2 repair | AVForums) it looks as there is a separate pcb for the preamp and filter section.
You'll need to find out what the input wires are and what voltages are needed.
In stead of trying to repair the PSU and amp, I would go for changing these to something like this:
IRS2092 CLASS D Audio Power Amplifier AMP Kit 200W MONO Assembled Board UK | eBay
and
500W amplifier switching power supply board dual-voltage PSU +/-55V L164-11 | eBay
If the driver is a 4 ohm unit, chose PSU with +-40cd, if it is a 8 ohm unit chose 55 Vdc, both giving some like 200 Watt as output.
Be very carefull witht the SMPS PSU, we are talking about very high voltages, which can kill you!! So make sure you know what you are doing
Sorry to bvring up an old thread but I still havent got round to sorting this
I checked out the amplifier and power supply board Baldin recommended and they do seem to fit my needs, But after doing some research I came across this amplifier board:
WONDOM | STORE
It says rated for a 3ohm driver at 400watts. My Kef subwoofer is 6ohms (written on the magnet). From what I understand, If I connect my kef sub to this amplifier the power output would decrease by half to 200watts and work with my sub. Do you think this is suitable?
I can also use a normal power adaptor from a laptop or similar to power it up. Saves me having bare/ exposed high powered circuit board.
Please let me know, Appreciate the help
I checked out the amplifier and power supply board Baldin recommended and they do seem to fit my needs, But after doing some research I came across this amplifier board:
WONDOM | STORE
It says rated for a 3ohm driver at 400watts. My Kef subwoofer is 6ohms (written on the magnet). From what I understand, If I connect my kef sub to this amplifier the power output would decrease by half to 200watts and work with my sub. Do you think this is suitable?
I can also use a normal power adaptor from a laptop or similar to power it up. Saves me having bare/ exposed high powered circuit board.
Please let me know, Appreciate the help
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