I have just bought a sony bdp-s490 3d blu ray player. tried a 3d blu ray and the blu ray plays ok but not in 3d. I know it is not the tele or the glasses, because I can see the tele in 3d when watching straight from the tele. I have got the blu ray going through a yamaha z7 amp. could it be that the 3d is not passing through the amp, or incorrect cables (I have just ordered new hdmi cable) but if it the amp that is the problem, how can I get around this?