sound card/ amplifier for bookshelf speakers

[ofekfischer]

Greetings,
I have a pair of active bookshelf speakers (with AUX cables coming out of them). The speakers are connected through a "center unit" with radio, cd player, line in etc. I would like to connect the speakers directly to my PC, but when I do so the output volume is low. What do I need to connect them directly (without the "center unit") to my PC and get louder audio?

 

[americanaudiophile]

Makes and models would help.
If the speakers don't have their own power supply they are not active.
Many makers use the cheapest connector they happen to have to connect passive speakers to the "center unit" so even if they are 3.5mm plugs the speakers may not be active.

 

[ofekfischer]

Makes and models would help.
If the speakers don't have their own power supply they are not active.
Many makers use the cheapest connector they happen to have to connect passive speakers to the "center unit" so even if they are 3.5mm plugs the speakers may not be active.

the system model is CD 1260 by Graetz, can't find anything about it. There are only 3.5mm cables coming out of the speakers, nothing else.

 

[americanaudiophile]

Sounds like the speakers are passive so you can't bypass the receiver that came with them without adding an amplifier.