LAB REPORT RICHARD ALLAN A21 (Vintage)

摘要

This early solid-state Class A amplifier is a far more esoteric proposition than either the Leak Stereo 30 [HFN Oct '10] or even the Goodmans Maxamp 30 [HFN Dec '10]. Rated at 10W/6ohm, it was possible to squeeze 9W/8ohm and 7W/4ohm at 1-2% distortion with very little advantage under dynamic conditions [see Graph 1, below]. But while the Leak and Goodmans bested the A21 for power (the Maxamp 30 could achieve 2×22W/8ohm for the same distortion), the Class A midget offers far greater consistency in its distortion versus frequency. Instead of incurring the typical increase in THD at higher treble frequencies, the A21 holds true to within 0.03-0.05% from 20Hz right up to 40kHz at 1 W/8ohm. Subjectively this is a very favourable result [see Graph 2, below].