Connecting older AV receivers to secondary amps

[Mthumann]

What is best way to take advantage of another amps capabilities for a 2.1 system when the AV receiver has no pre outs?

 

[Mthumann]

? I only utilize 2 channel stereo and sub.Your solution seems to imply the Pioneer will now be just sending line level signal only from its fronts and wire both sets of wires from Nakamechi speaker posts? The Nak is higher rated and better quality but the power is actually a little less than the pioneer.Because currently I use the pioneer fronts to drive the monitors bi wired and I use the pioneer's Speaker B out to a line level converter to one of the Nakamichi's AUx inputs. I do get some power ( Nak rated at 80 W into 8 ohms) to the woofer bases. With this set up I can turn the pioneer A speakers off and adjust the adapter mini screw and nak volume. It sounds muddy obviously but I'm only hearing woofers. I just wanted to be sure to get the best quality signal using BOTH amps. But I assume with your response just use the Nakamichi's to drive everything? AV will still be the input, the volume, tone and balance controller?
And yes I realize best overall solution is to get an AV with pre outs, or invest in new separates like Emotiva!