two main options
Keep these in mind:
a) The Tape out comes BEFORE the volume control.
b) The Preamp out comes AFTER the volume control.
Now,for the methods. Unit one is the Marantz. Caveat will explain why later.
1) You can connect the TAPE OUTPUTtape output of one unit to an AUX input of the other unit. The preamp section on the first unit will be bypassed. When you select the AUX input on the second unit, whatever is selected on the first unit will be sent to the second unit.The first units volume control will have NO effect on that signal.
2) You can connect the PREAMP OUTPUTtape output of one unit to an AUX input of the other unit. You WILL be sending the signal through the preamp of the first unit. When you select the AUX input on the second unit, whatever is selected on the first unit will be sent to the second unit. The first units volume control WILLl have an effect on that signal.
Caveat: if you use the Yammie as the first unit and use the zone out or a tape out, only analog signals will be passed to the Marantz. Digital sources will not.
2a) If you use the Marantz as the first unit, you can put a "Y" connector between the preamp out and the main in, feed one side back into the main in and the other to the AUX input of the Yammie and use the amps in both units. Dunno if his can be done with the Yammie.