Hello! I have just purchased this kit from a shop here in Norway.

Yesterday,i assembled the kit ,and tested it on my sound-sytem, when i activate the Vocal reduction the sound becomes very strange, as if you put a loudspeaker element into a tube, i have checked and re-checked that all the components are correct and soldered into the correct positions.

I cant find anything wrong, can anyone please advise me what to doo??

As indicated, the vocal reduction circuit works with most but not all recordings. It is important that the voice is recorded in the exact center of the soundstage for best results. In some cases, it might sound funny. Sorry, but it is impossible to determine whether there is a problem or not. Try a mono recording, volume should be reduced.