I seriously doubt the issue has anything to do with your amp. In my experience, some speakers just don't open up unless you open up the volume control a bit, as you have found. I don't know exactly what this is attributed to, but I think it has to do with the driver design and mechanical stiffness. In my experience, Dynaudios can be this way. I'm not Dynaudio bashing. In fact I think their speakers are very well made and engineered, but they don't let go of the music unless you play them a little louder.....a bit too loud for my listening habits / listening distance.
You might try breaking them in more. Place them face to face with maybe just 4 inches of space between them and wire one speaker out of phase. If you can, send a mono signal to the speakers, so they're both playing the exact same signal. You should be able to turn the volume up a quite a few ticks higher than normal and not hear much more than bass sounds coming from the backs of them. You can also cover them with a blanket or something to keep their back waves from radiating too loudly and also gently plug the ports with socks (clean ones
![Laughing :lol:](https://www.audiocircle.com/Smileys/audiocircle/sm_lyellow.gif)
). Play dynamic music with good bass. This should loosen up the drivers' rubber surrounds a bit and may also help break in some of the crossover components a bit also. This is pretty standard break-in procedure, especially if you are away at work during the day. I'd do this for maybe 2-3 days, assuming they've already broken in a little bit by the previous owner and you.