I hope to use my incoming HE-6 out of the speaker posts on my HK 3390 this weekend if all goes well. Good choice on the Harman Kardon btw, they generally shame the likes of Denon/Onkyo/Yamaha from MY EXPERIENCE. They have truly crystal clear, overpowering amplification with less distortion, at a fraction of the price of the others generally speaking. Plus, the lowball their numbers more than anybody besides NAD. I had the k340 a couple of years ago that SPANKED the pants of my roommates $1200 Denon in terms of power, clarity, and NO distorion even at deafening levels. The HK cost me $300 or $400 lol, I can't remember. It was rated at 55 WPC versus my roommates 110-125 WPC (can't remember exactly)!
Lol that sounded pretty biased and ranting lol...just count me as one who is truly impressed with HK performance, as I have heard many other heavy hitters in the same class over the years.
-Daniel