These loudspeakers are active, not passive, so they can only work when connected to a Marantz amplifier if the amplifier has a line output (pre-out) or if you directly connect an audio source to their RCA input. They are not passive speakers that can be connected directly to a conventional amplifier without a pre-out, because they have a built-in amplifier (class D) and require their own power supply.

In summary:
- They are active loudspeakers with a built-in amplifier.
- They have RCA inputs for connecting audio sources.
- They are not passive loudspeakers that can be connected directly to an amplifier without a pre-amplified output.
- To use them with a Marantz turntable and amplifier, the turntable must be connected to the amplifier, and the amplifier must have a pre-out or you must connect the turntable directly to the speakers via RCA, bypassing the amplifier.