Wow, I'm impressed with the provided solutions here. Especially the contributions by users like burkhardi and JohnBoyZ.
Not to offend any-one here, but I think by re-using the original PSU, the problem of heat which partly caused these PSU from dying remains as well.
Therefore using the "LM317" method as described here
, is in my opinion a bad idea as well.
With this method, the LM317 still needs to get rid of 6 to 9 Watt of heat.
On top of that I think this heat might even harm the rubber-like construction of the sub-woofer speaker as well.
Therefore I tried the method with a step-down dc buck converter.
Essentially it is technically the same as the original PSU, though by splitting the step-down in 2 parts, the heat in the sub-woofer box is reduced.
To start, I removed all the internals of the original PSU and removed the mains connection as well.
Took a 19,5 Volt DC laptop power-supply for the first step down. Though I used one providing 2 Amp, I recommend one with more head-room i.e. 2,5 Amp.
Hot-glued an aluminum strip with the adapter-plug for the laptop power-supply on the position of the original mains.
Since I'm lazy with regard to soldering, I used this
I connected all the original cables to this PCB (Very handy that you can chain the 19,5 Volt further on).
Hooked up the Soundbridge front-unit, and adjusted the output of the DC-converter to 9,5 Volt by using a cheap panel volt-meter at the output of the PCB (again, the double connectors are very handy here to connect the volt-meter).
Reused the black gum from the original PSU to stick the new PCB to the bottom of the plastic PSU box.
Used some tape to glue the new PSU back to it original form, mounted it back in the sub-woofer box, and used a bit of sealant to close the sub-woofer.
I estimated the costs of this method around € 50,-, including the voltmeter, tape and sealant.
Since I bought an already broken unit, I was surprised about the sound of the R1000.
However I have a feeling that the sound of the sub-woofer is a bit strong compared to the sound of the front-unit.
Maybe somebody with a bit more knowledge in the area of speakers can provide some advice.
I tightened the screws holding the subwoofer already, which gave some improvement.
Maybe there is something wrong the inlay of the wadding.