I recently purchased the 990 from Outlaw brand new. So far I really have enjoyed the SSP but I noticed this weekend my Outlaw LFM 1 Compact sub will not activate when the 990 is in stereo mode playing an audio CD. Only in 5 channel stereo will it activate (as well as Dolby movie and dts modes). And, yes I have check the on-off switch on the sub. I also checked the 2-Channel Subwoofer offset and it’s at 0db, no offset. I tried stereo mode, bypass, upsample and the sub will not function. It clearly states in the 990 manual I should have left and right fronts and the sub woofer functioning in stereo mode. What else should I check? Is the unit defective? I think it worked previously but I could not tell you for sure. What do I do?