Dear Lewm, I have tried your suggestion and it has brought a big improvement to the sound image and, surprisingly, to the tonal balance, now with less enphasis on the higher frequencies. I guess the turntable huge acrilic case was acting as a resonance box.
Unfortunately my wife is not so happy because I have brought the music rack (double width and quite high) also 5 feet into the room to be aligned to the speakers plane and this is our living room as well :-). So far I got permision, so lets enjoy it.
If in the future I evolve to a Pre-Power combo I'll be able to move the phono pre together with the turntable to a side space, following the recommendations to other posters.
Thanks to all of you guys!