Rotel RSX-1057 AV Receiver Comment and Measurements
The Martin Logan speakers used for the review are, as Fred notes, a difficult load. But it must be noted that Fred has used other receivers, including a comparably priced Pioneer (review in progress) that drives those speakers with more ease at higher levels than the Rotel. However, we plan a Take Two to this report using more conventional speakers of the sort most likely to be used with the receiver. Stay tuned.
All measurements were taken on the left channel.
The S/N (A-weighted, 2.83V into 8Ω) measured –93.6dB. With the level control set to "81" a 100mV input produced a 26.4V output for a gain of 28dB.
With only two channels operating at 1kHz, the Rotel clipped (1% THD+noise) at 165Wpc into 8Ω and 228Wpc into 4Ω (to the nearest Watt).
Driving all five channels into 8Ω, the Rotel delivered 120Wpc at 20Hz and 119Wpc at 1kHz (to the nearest Watt) before clipping (1% THD+noise). The protection circuits tripped during the 20Hz measurement, but the unit operated normally again when the test signal was disengaged.
Driving all five channels into 4Ω the Rotel delivered 139Wpc at 20Hz and 145Wpc at 1kHz (to the nearest Watt) before clipping (1% THD+noise).—TJN