Page 1 of Who`s the daddy?

In the red corner - me with Yamaha 5 channel receiver (RXV596)
In the blue corner - missus with Denon "separates" system
The Denon "separates" are connected together by ribbon cables - there are no pre-outs for off-board amplification.

To keep madam happy (i.e. one set of front speakers and the Denon in service) I`m running the fronts (in my home cinema set-up) off the Yamaha`s pre-outs, amplified by the Denon.
I`m not happy with this as it`s definitely a compromise and I have to fart round with the levels.

The only "pre-out" that the Denon has is for an external tape-loop.

My question is - is this a valid pre-out? Can I use it to send CD (or tape) signals to my Yamaha so that the Yamaha becomes the daddy again?
Is this a go-er or fraught with problems (e.g. is that external tape loop pre-out on the Denon already amplified?)

Cheers,