Taking the analysis road very slowly as I don't have time right now for an extended session. Turned off all lights, fans, etc. and then only turned on pre-pro and amplifier. No hum or noise whatsoever. Will start by turning on most common appliances first to see what gives. Then will move on to inputs/components. Would love it if gremlins struck and noise just magically went away!
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75" 4K HDR Sony XBR 75X95k mini-LED TV
Marantz AV7706 pre-pro
OPPO UDP 203 4K Ultra HD Blu-ray Player
Mirage HDT Speaker System (LCR [OM-5s for L&R and HDT-F for center], SR, SL, SBR, SBL [HDT-Rs])
Dual SVS PB12-Plus Subs
Outlaw Audio Model 7900 Power Amp w/Dual Emotiva CMX-2
AudioControl BijouTM THX� Equalizer
Rega RP1 Turntable
Dual Panamax M5300-PM Power Conditioners
Dual Monster Power HTS 2500 Power Conditioners
Dual Monster Power HDP 1800 Power Conditioners
Clearplay Blu-ray Player
Motorola VIP1200 HD cable receiver
Logitech Harmony Elite Remote