So exactly which power filter did you buy? Sounds like I might have to head down to my local MediaMarkt too, 'cause the other things have all drawn a blank on my unit.

Well, they have three different models, all from Freitag Elektronik. I think they were rated 5, 10 and 20 A, respectively. I was not sure how much the Empeg needed, so I bought the 10A version to be sure. It turned out the smaller model would have been sufficient too, as the Empeg has a 3A fuse.

The 10A version costs fl. 19,95 which is about 9 Euro. It appears the Euro sign was lost in my previous post (although it did show up in preview).

I have also seen a Pioneer 4A power filter at a local small Halfords store. I guess this one should be sufficient too. And it is also a lot smaller than the Freitag one.

And yes, only the head unit needed filtering. I assumed this, because - like I described in a previous post - the alternator whining was also gone when I connect the head unit to the AC adapter.