Jtwrace,
Your amp's input impedance is not as relevant as its sensitivity, here. Look for a number that's power yielded for a given RMS input voltage, OR a gain factor. The Hera has a very low output impedance, so a 100K amp input is a very easy job for it, in that sense. My current monoblocks give 250 Watts @ 1V, but a previous amp gave only 25 Watts @ 1V - those needed a TON of line gain!
One thing to consider - I believe Athena has a much lower gain than the Hera II. Call up Mark @ Rogue (he designs the gear); he's incredibly helpful and will help figure out exactly what's right for your system. I'm just an armchair quarterback here; he's the real expert.
