ARC "lied" about the power of the Reference 75!
Per the Stereophile testing:
Audio Research specifies the Reference 75's maximum power as 75Wpc (18.75dBW into 8 ohms) at typically 0.6% THD. Figs. 5, 6, and 7 show how the THD+noise percentage increases with power into 8, 4, and 2 ohms at 1kHz from the 4 ohm output transformer tap. We define clipping as when the THD reaches 1%; the Reference 75 doesn't quite meet its specified power at that level of distortion, delivering 61Wpc into 4 ohms (14.8dBW, fig.6), and lower powers into the other impedances: 43Wpc into 8 ohms (16.33dBW, fig.4), and 40W into 2 ohms with one channel driven (10dBW, fig.7). However, relaxing the definition of clipping to 3% THD, the Reference 75's 4 ohm tap gives 46.5Wpc into 8 ohms (16.67dBW), 70Wpc into 4 ohms (15.45dBW), and 94W into 2 ohms (13.7dBW). Slightly more power was available from the 8 ohm tap into 8 ohms (fig.8): 70Wpc at 1% THD (18.45dBW) and 78Wpc at 3% THD (18.9dBW).
This amp will not be useful except for very low volumes!
Per the Stereophile testing:
Audio Research specifies the Reference 75's maximum power as 75Wpc (18.75dBW into 8 ohms) at typically 0.6% THD. Figs. 5, 6, and 7 show how the THD+noise percentage increases with power into 8, 4, and 2 ohms at 1kHz from the 4 ohm output transformer tap. We define clipping as when the THD reaches 1%; the Reference 75 doesn't quite meet its specified power at that level of distortion, delivering 61Wpc into 4 ohms (14.8dBW, fig.6), and lower powers into the other impedances: 43Wpc into 8 ohms (16.33dBW, fig.4), and 40W into 2 ohms with one channel driven (10dBW, fig.7). However, relaxing the definition of clipping to 3% THD, the Reference 75's 4 ohm tap gives 46.5Wpc into 8 ohms (16.67dBW), 70Wpc into 4 ohms (15.45dBW), and 94W into 2 ohms (13.7dBW). Slightly more power was available from the 8 ohm tap into 8 ohms (fig.8): 70Wpc at 1% THD (18.45dBW) and 78Wpc at 3% THD (18.9dBW).
This amp will not be useful except for very low volumes!