I don't have an H3000 in front of me at the moment, but from my work on the H3000 plug-ins we did there's no noticible tonal difference with any of the H3000's I tested against. It might be important to make sure you've got the levels set correctly on your H3000, there's a level setting guide in the original manual here: https://www.eventideaudio.com/support/downloads/h3000-series-user-manual
I also don't recall if the H3000 had a pre-emphasis setting, but if so this could explain what you're hearing. Try turning that off if there is one (though I don't think there is).
If it's none of these things, and if the tonal difference is significant, I think it's most likely your H3000 needs calibration or repair. There is a calibration procedure in the service manual here: https://www.eventideaudio.com/support/downloads/h3000-service-manual, or the Eventide support folks can help refer you to a qualified repair tech.
Good luck,
Dan
