Your question has similar answers to another thread titled
Amp Selector. Scroll down and see some of the answers that were posted.
Your speakers are on the sensitive side, rated by Klipsch at 98 dB/watt/meter. Klipsch is somewhat infamous for exaggerating on their speaker's sensitivity, but they are still among the more sensitive home audio speakers around. I understand that you may like using that Adcom amp, but you probably don't need it to drive your Fortes.
AVRs are marketed so that none of the lower powered models include preamp outputs that allow using an external amp. The least expensive model I know of is the
Denon AVR-X3400H, that offers preamp out put jacks for all seven channels. If anyone knows of a less expensive AVR that offers this for at least the front left & right channels, please post it