Boisehomes, just checked the specs on the LS 26. Seems like most (maybe all) ARC preamps and line stages (including the LS 26) should not have their main outputs loaded with less than 20K Ohms. If you load both output mains, the formula for computing combined impedance is L1 x L2/(L1 + L2). So, e.g., if Main 1 is used for an amp with an input impedance of 300K Ohms and Main 2 is used for a self powered subwoofer with an input impedance of 20K Ohms, the combined impedance would be 18.75K Ohms -- too low.