Integrated Amplifiers

Tested without the 300Bs in-circuit, the L2i-SE put in a sterling performance. Power output is comfortably higher than its 100W/ 8ohm rated specification at 2x130W/8ohm and 2x210W/4ohm and there's sufficient in reserve to accommodate 180W, 333W and 234W into 8, 4 and 2ohm loads, respectively, under dynamic conditions [see Graph 1, below]. Power is limited to 128W/1ohm (or 11.3A). Distortion trends downwards with increasing output from ~0.01%/1W to 0.009%/10W and 0.0055% at the rated 100W (all re. 1kHz/8ohm) but increases at higher frequency from 0.1%/10kHz to 0.2%/20kHz (all re. 10W/8ohm). Gain is low at +24.1dB, but ideally suited for use with 2V line output sources, and the S/N is fabulously wide at 96.5dB. The response shows a subsonic roll-off of –0.1dB/20Hz and –6dB/2Hz while extending out to –0.1dB/ 20kHz and –1.0dB/100kHz.

Measured via its balanced preamp, VR's AKM AK4497-based DAC stage offers a maximum 4.6V output, and 108dB S/N ratio, from a low 25ohm source impedance. An acceptable ~125psec jitter rejection is achieved (all sample rates) while distortion falls to a minimum of 0.00035%/1kHz and 0.00055%/20kHz over the top 30dB of its dynamic range [see Graph 2], albeit peaking at 0.1-0.15% over the top 10dB. The default NOS filter offers responses of –5.0dB/20kHz, –5.4dB/45kHz and –6.9dB/90kHz with 48kHz, 96kHz and 192kHz files, respectively, trading a very limited alias rejection for zero time distortion. The minimum phase filter offers a superior 70dB image suppression and flatter –1.8dB/20kHz, –2.7dB/45kHz and –4.1dB/90kHz responses. PM