Surround-Sound Preamp-Processors

The frequency response of the FMJ P7 measured –0.03dB at 10Hz, –0.00dB at 20Hz, –0.08dB at 20kHz, and –0.46dB at 50kHz. The amplifier's gain measured 29dB. The S/N at 1W into 8ohms was –106dB, A-weighted. THD+noise at 1W into 8ohms measured 0.005% at 20Hz, 0.006% at 1kHz, and 0.005% at 20kHz. THD+noise at 2W into 4ohms measured 0.004% at 20Hz, 1kHz, and 20kHz.

Into an 8ohms load, with 7 channels driven, the 7-channel Arcam clipped (1% THD+noise) at 153W per channel at 20Hz and 156Wpc at 1kHz. With 6 channels driven, it clipped at 157Wpc into 8ohms at 20Hz (227Wpc into 4ohms) and 167Wpc at 1kHz (237Wpc into 4ohms). Driving 2 channels, the P7 clipped at 199Wpc into 8ohms and 285Wpc into 4ohms, both at 1kHz.

All measurements were made at 120V, with the readings taken on the left channel. The output power results are rounded to the nearest watt.—Thomas J. Norton