Hi OP:
I think that swapping amps for a tonal imbalance problem is the second worst way to do so. The first is to buy new cables.
Your description sounds like you are missing bass, not mids per se. There’s a couple of things I think you should try. First, use the Luxman tone controls, they are really good. I’d start by reducing the treble a couple of notches. Next, consider your listening location. Your ear should be at or below the tweeter’s axis. You may need to tilt the speaker back or lower your seat or separate your seat and speaker somewhat. The pooint is, you may need to be much lower than you are, and don't be afraid to listen at the mid woofer's axis, some speakers just sound better there.
Next of course is the room. An overly reflective room with solid windows and drywall will sound much brighter for all speakers.