udog
Having just read a review in Stereophile of my Audio Physic Step Plus speakers. The author states that his Shindo Haut-Briton Power amp (20wpc) couldn’t drive the Step
I believe it, a 20w tube amp, and knowing Japanese probably very low feedback.
Audio Physic Step having been tested at only 84db efficient, and with an impedance/phase curve (linked)
The one in the Stereophile review I believe "y" axis maybe a misprint.
This must be another one they did, and could be the right one.
3ohms from 150hz to 400hz and then 5ohms with -45 negative phase angle.
https://www.stereophile.com/images/119APStepfig1.jpg
Cheers George