Telescope_trade... I, also, haven't heard the Hyperions. As Gmood1 says, the ZR1600 input is balanced (remember this is a Prosound amp) but it works fine single ended using the Radio Shack phono/rca adapter. With regard to preamps, the ZR1600 input sensitivity is adjustable.
Choices range from 0.316 to 2.45 vrms for full output (600 watts into 4 ohms) so it would be easy to match up with source electronics if you want to use a passive preamp. The ZR1600 also has volume controls, separate for both channels, which can be bypassed if you think they degrade the sound.
The only drawback is that the amp does use a fan, which makes some noise. The best solution (the one I use) is to hide the amp away in the cellar or a closet. There is also a simple mod to change the fan to a very quiet model, and, for home audio use, it's been reported that the amp does not overheat with the fan disconnected.
It is solidly built (for rough Prosound use) and has a 5 year warranty.