In some cases, such as the HiFiMAN HE-6, which has notably low sensitivity and thus requires several watts to power adequately, the MZ2 and MZ3 probably will give you a satisfyingly loud and full listening experience. Since the unique circuit of LTA amps reacts very little to different impedances, it is mostly a matter of sensitivity when it comes to which headphones the MZ2 and MZ3 works well with.
Whether it can "drive my headphones" often just means "will I prefer how my headphones sound with this amp?" We've read many accounts of people thinking their HE1000 or HD650 has never sounded better than on a MZ2 or MZ3. I've also read one or two accounts of people saying the opposite.
We don't know what you like, but we do know that we've read far more mentions of the MZ2 and MZ3 sounding good with all kinds of headphones than not.
The second generation of the product that started LTA, the microZOTL MZ2 contains years of product development in one compact chassis. Built on the 6SN7 tube, the MZ2 remains the reference introduction to the unique ZOTL circuit.
Small and mighty. The highest expression of the patented microZOTL technology as a headphone amplifier, a preamplifier, and integrated amplifier in a desktop-sized package.