I alwyas recommend that people use an external amp to power the other speakers. If memory serves me well, the RXV 673 has a pre-amp out for Zone 2. This allows you to connect an external amplifier on zone 2 to power your 3 pairs. This will be the safest way of doing this. You can get some inexpensive external amplifiers from: Emotiva, HTD, Parts Express and a few others to do this.
2/9/14 at 8:31am