For years I too have had a hum from my McIntosh MC207, and because of this thread and Ivans suggestion, I purchased the Emotiva CMX-2. The hum has finally disappeared both from the amp itself and through the speakers.
It worked by plugging MC207>Emotiva CMX-2>PS Audio Quintet>Wall. 
It did not work by plugging Amp>PS Audio Quintet>Emotiva CMX-2>Wall. 
So a big thanks to Ivan for the suggestion. 
Hope it works for you Mouse. 
Ron
__________________
Ron
Processor: McIntosh MX170, Amp: Legacy Audio i-V7, Digital: Benchmark DAC3B, Roon Music Player, Oppo UDP-205, Apple TV 4K, Fire TV Stick 4K Max, Analog: Gold Note Pianosa Turntable, Gold Note PH-10 Phono Preamplifier, Donatello MC Cartridge, Speakers: Legacy Audio Signature SE Natural Sapele Pommele, Silverscreen HD Center, JL Audio e112-Gloss Sub
|