I intend to buy a receiver soon, but for the ones i'm interested in, there are no reviews to be found.
i'm going to use it only with preamp outputs, so preamp sound quality is primordial for me.

At first i thought about the Integra DHC-40.2 but i think i can get the same quality or maybe better with a receiver, at a lower cost.

I'm interested in those:
Integra DHC-40.2
Denon AVR-3312CI
Marantz SR5005
Harman Kardon AVR3600
Yamaha RX-A700

i repeat, i will not use the built-in power amps, but only the preamp outputs, so what's most important for me is sound quality.

What would you recommend, and why?
cost no object.(does not mean i'm rich).