Newbe Help what AV amp


Hi, almost picked up ATC SCM40s for my front 2 channel , my source is a Denon 4010UD bluray player, I tried the ATC SIA 2-150 amp.
The sound was fantastic with CDs playing direct mode but the minute I tried a Concert DVD or a concert Bluray the sound was awful..
Is it a problem with the connection or do I need a AV Amp.
Anyone tried Primares with. ATCs or should i stick to ATC amps?
thks
rainmonkey
Sorry, the link was supposed to be for the manual.[http://denon.co.uk/DocumentMaster/UK/DBP4010UDE2_ENG_IM_204.pdf]
I should have mentioned, the Y connector works sometimes, but not always with the best sound.
Thks Hifivn,
Tried the 2 channel setting n it sounded muddy, Ran it last week with a sad Onkyo AV amp , The sound was much better.I guess ill have to go in for an Av amp for the DVD part,,,a bit of a bummer as i was hoping to keep it totally 2 channel. I really dont want to add a centre or a sub.