Hi All,
I have the Kube (sp2051) for the Kef R107 speakers.But I do not have the power supply that goes with it. The power supply is as far as I have found out is an 18V 5 W unit with a Din connection that goes into the Kube.
I have read that it's a simple enough job to convert a normal ac adaptor by adding a Din connector plug to the output of the adaptor. It's only 2 pins of the Din that are used and this can be found by opening the Kube and looking at the Din input.
Is this about right? An 18v AC adaptor with 5W power output and adding a Din plug should work? What about current? Even better does anyone have a spare Kube PSU for R107 for sale?
Cheers,
Roy
I have the Kube (sp2051) for the Kef R107 speakers.But I do not have the power supply that goes with it. The power supply is as far as I have found out is an 18V 5 W unit with a Din connection that goes into the Kube.
I have read that it's a simple enough job to convert a normal ac adaptor by adding a Din connector plug to the output of the adaptor. It's only 2 pins of the Din that are used and this can be found by opening the Kube and looking at the Din input.
Is this about right? An 18v AC adaptor with 5W power output and adding a Din plug should work? What about current? Even better does anyone have a spare Kube PSU for R107 for sale?
Cheers,
Roy
That's very true, that's why I really have to know which it is.
I have already bought an 18v 5 watt AC to DC adaptor(hasn't arrived yet)...Obviously will do nothing with it until 100% certain of the set up.
Cheers
Roy
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It would be worth looking on the unit and seeing if any internationally recognised symbols are near the adapter input. Do a Google search for AC DC symbols.
A quick look at the internals should also confirm what type of supply is used. AC will have all the rectifiers and large reservoir caps present in the unit. A DC supply will probably not have such large caps in the unit and there will almost certainly (but not 100% guaranteed) be no bridge rectifier.
A quick look at the internals should also confirm what type of supply is used. AC will have all the rectifiers and large reservoir caps present in the unit. A DC supply will probably not have such large caps in the unit and there will almost certainly (but not 100% guaranteed) be no bridge rectifier.
Its the last picture that's of interest and that does seem to show a couple of large reservoir caps. Could do with seeing more of that area really but it looks like it is AC.
I found this:
http://www.kef.com/uploads/files/en...eries_Model_107_Installation_Instructions.pdf
which seems to confirm its AC as well.
Now for another complication
The circuitry uses TL072 opamps which suggest it will all run on a dual plus and minus or as its correctly written a -/+12 or 15 volt DC supply.
That type of supply can derived from a single two wire AC input or a three wire input.
So its important you know which. The clues would be the connections to the DIN socket.
Look at the diagrams. The first one is the conventional (and best) method of using a transformer with a dual secondary winding that has a tapping in the middle. So that would be a three wire feed from the adapter.
The second is using a single secondary winding and is an option only when the currents involved are small (which is as here to be fair).
So it could be either.
I found this:
http://www.kef.com/uploads/files/en...eries_Model_107_Installation_Instructions.pdf
which seems to confirm its AC as well.
Now for another complication
The circuitry uses TL072 opamps which suggest it will all run on a dual plus and minus or as its correctly written a -/+12 or 15 volt DC supply.
That type of supply can derived from a single two wire AC input or a three wire input.
So its important you know which. The clues would be the connections to the DIN socket.
Look at the diagrams. The first one is the conventional (and best) method of using a transformer with a dual secondary winding that has a tapping in the middle. So that would be a three wire feed from the adapter.
The second is using a single secondary winding and is an option only when the currents involved are small (which is as here to be fair).
So it could be either.
Attachments
Daddy Pop, I recently built a PSU for a KEF Kube 200 (similar to what you have). I can confirm as Mooly says that is AC. I had to order some parts from Farnell or Maplin (can't recall which right now). I can send you some photos of what I built if you want to replicate it. It's been running very happily for about 6 months.
So that quote seems to confirm it then.
Something like this should be suitable:
CAMDENBOSS - CTFC12-18 - TRANSFORMER, 12VA, 2 X 18V | CPC UK
This is rated at 12 va which is approx. 0.33 amps per winding. Derated for supplying a bridge and reservoir cap and it would be good for around 180ma DC per rail which will be way in excess of what is needed.
Edit... CPC do free delivery on web orders over £5.00
Is there enough room in the unit itself to put a transformer. There are other case styles available such as low profile toroidals and potted rectangular ones. The type shown (and toroids) are the easiest to mount though.
Something like this should be suitable:
CAMDENBOSS - CTFC12-18 - TRANSFORMER, 12VA, 2 X 18V | CPC UK
This is rated at 12 va which is approx. 0.33 amps per winding. Derated for supplying a bridge and reservoir cap and it would be good for around 180ma DC per rail which will be way in excess of what is needed.
Edit... CPC do free delivery on web orders over £5.00
Is there enough room in the unit itself to put a transformer. There are other case styles available such as low profile toroidals and potted rectangular ones. The type shown (and toroids) are the easiest to mount though.
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