Something weird has just happened in my system.
I am running a CD player into the Modi multibit via coax, which is feeding the Jotunheim.
Everything was fine until I put in a classical CD and when the music started there was a persistent ringing in the left channel. The ringing would rise and fall depending on the loudness of the music, and it came mostly during higher pitched stuff.
Thinking it was my headphones, I plugged them into another source and played a variety of music and there was no ringing. So it was not the headphones.
Trying to isolate the problem, I played some more CDs in the original setup and the ringing started happening mostly on classical CDs, but would occasionally be heard on a pop album. So I disconnected the Modi from the CD player and plugged it into my laptop via USB cable. Played some music from youtube and the ringing was still there, so I knew it wasn't my CD player.
Then I plugged Modi back into the CD player, then Modi into a different amp to see if it was the Jotunheim doing it. I heard the same ringing in the second amp, so it was not the Jotunheim. It had to be the Modi since it was the only thing that didn't change.
So I simply turned Mimby off and back on again. No more ringing. Has anyone else experienced this?