Confused about the Japanese 'r'

Hi,
I recenlty started learning Japanese and I'm somewhat confused about the pronunciation of the 'r'. When I listen to the pronunciation of the ra/re/ri/ro/ru syllables from various sources online I do hear a short 'l' (tap to the gums above the back of the upper teeth) for the 'r'.
However listening to Japanese word/phrases I clearly hear an short r (tap to the back of the upper teeth with the upper part/tip of the tongue, NOT the rolling English r but more like the Dutch r) instead of a short 'l'. Although the short 'l' and 'r' sound similar, when I use the short 'l' instead of the short 'r' it doesn't sound right.
Any help or comment would be appreciated.

To avoid repeating myself:

ra ri ru re ro or la li lu le lo??!! | Japan Forum

When is different not different? | Japan Forum

Thanks nice gaijin,
Your description of r is exactly what i was thinking of (e.g. perro, Rotterdam, short tap to the palate), thanks and sorry for not searching the forum first before posting.