Why do my ears ring with my new amplifier?

"I don't think that the high frequencies are the problem."

You may not think HF's are the problem but I think you might be mistaken. A funny thing happened to me a while back when I listened to a DIY Class D amp. Initially, the first 5 minutes it sounded all right but certainly not perfect, transparency was amazing but.....after about 15 minutes I started getting a headache. I'm not being sarcastic, this really happened. The problem immediately went away when I replaced the amp. The REAL dilemna was I never could figure out what was causing the headache. The same amp in the owner's system didn't do this.

If you're not listening too loud, which could certainly cause ringing, you most certainly have an issue with the upper frequencies. The cause is less clear but it could include the amp/speaker interface, most likely IMHO. Room treatments and speaker placement may help ameliorate the issue. It's tough to tell without knowing everything. Do you have any audio buddies or a wife that could chime in with their opinion? It might help narrow things down a bit.

Noom, it is my experience that if you have to turn up the volume to hear one thing at the expense of something else, in your case to hear instruments in the background the problem isn't necessarily too much detail as a general lack of overall resolution of the system. As to what is the specific cause, it could be anything and not necessarily the amplifier.

A very good system should be flat and smooth enough to allow the listener to hear everything on the recording even at moderate levels. If you have to turn up the volume to an uncomfortable level this would indicate to me a balance and/or lack of resolution issue somewhere in the chain. Rooting out the problem can be a tough call and could be a multitude of issues. At a basic level it is most important for the amp and speaker to be electrically compatible with each other. Of course a good source component and preamp are most important for fully realizing the potential. It is difficult for me to separate out one thing over another in these matters as everything, including room, placement, components and last but not least cabling are all important for realizing satisfying music in the room at reasonable levels. The devil is in paying attention to all the details.