System problem

Hi all, wonder if anyone can help me here. Was listening to my system last night at a pretty high volume level. I went to turn it down to shut it down for the night and when I hit the down volume button on the remote the system dropped in volume and went almost mono sounding. Both left and right sound the same. Like someone put heavy. heavy blankets over the speakers. I thought a tube had blown in my preamp so I replaced them with new spares and no difference. Today, I plugged my monoblocks directly into my DAC/streamer and the same thing so I’ve eliminated my preamp as the culprit. Any ideas? My system consists of Wilson Maxx 3’s, Classe CAM600 monoblocks, EAR 912 preamp and PS Audio Directstream with Bridge 2. I won’t mention my turntable setup as I wasn’t listening to it when this happened. All drivers in the speakers are working, there is just minimal and muffled sound. Any suggestions would be appreciated. Thank you