New amp listening fatigue: Distortion or ??????

Hello All,

I recently acquired a used Denafrips Hestia/Hyperion amp/preamp combo for my second system. I traded a low power 300B amp for it. It’s class a/b with 80 w/c 8ohms and 150 w/c 4 ohms. I thought it would go nicely with my Denafrips Pontus2 and it does. My first listening session was about 1.5 hours long listening to Beethoven symphonies which I know quite well. My initial impressions were positive. The new amp produces a huge, well defined soundstage and effortless ability to project dynamics. Bass is strong and well defined. Treble is smooth and clean sounding. The mids are rich and accurate, but much more energized than the bass and treble. After an hour, my ears felt pressurized and were ringing and I couldn’t listen anymore. I usually listen around 75-80 dB max. I never heard any distortion or anything suspicious. I repeated the session next day with my other speakers with the same results. Is it possible that there may be distortion present that I can’t hear? Or maybe this amp highlights certain frequencies that irritate my ears?

In years past I discovered I have a sensitivity to certain frequencies in the midrange somewhere around 600 - 1000 Hz and I used to use a graphic EQ to lower the mids. I’ve also gotten rid of any speakers or amps that have that hump in the midrange. My current, everyday rig is a Hegel H95, using the internal DAC for music and video played through Philharmonic BMR Monitors. I never get tired listening to this set up and can listen for hours. The Hegel is clean and clear with a balanced, neutral presentation. The new amp/pre combo has a warmer, stronger more muscular sound and unfortunately, creates listening fatigue. I’m thinking of adding a Schiit Lokius EQ to tame the mids in the new amp. Thing is, I’m also trying to simplify my gear, gravitating towards smaller, lighter weight speakers and components. Maybe just get another Hegel for my second system?

BTW I always protect my hearing when using or loud equipment or around any other loud sound source. My hearing has dropped off over the years, but I still hear up to around 9,000Hz.

Has anyone had similar experiences with a new/different amp?