Before I received the HA160 I had probably never heard either my Sennheiser HD-580 nor my newer HD-650 headphones driven by an amplifier that had sufficient power. The sound is fabulous, and there are no more cringe inducing passages where the amplifier runs out of power. My old IC op-amp/tube hybrid amp, using an LM4562 driving a 6922 output stage delivered fine sound, but the plate starved tube just couldn’t deliver high levels cleanly, and useful tube life was only a few months.
The HA160 is superior in every way. There is no going back.