I performed the measurements on a different sample of the DeVore Fidelity O/baby from those that had been auditioned by Ken Micallef. It had the serial number B0510001. I used DRA Labs’ MLSSA system with a calibrated DPA 4006 microphone to measure the speaker’s behavior in the farfield and an Earthworks QTC-40 mike for the nearfield responses.
DeVore specifies the O/baby’s impedance as 8 ohms, with a minimum value of 6.75 ohms at 200Hz. Measured with Dayton Audio’s DATS V2 system, the speaker’s impedance magnitude (fig.1, solid trace) lies above 10 ohms for almost the entire audioband, dropping below 8 ohms only This lies below 4 ohms from 43–50Hz, from 85–148Hz, and from 8–14kHz. The minimum EPDR is 3.6 ohms at 46Hz and 3.33 ohms at 108Hz. Despite its high average impedance, which is close to 16 ohms, the O/baby will probably work best with a tube amplifier’s 4 ohm output transformer tap.
