Integrated Amplifiers

The core design of the 800.2 is taken straight out of the multi-box Nu-Vista PRE/PAS [HFN Mar '23] although the latter's over-cautious electronic protection – limiting its low impedance output to just 575W/2ohm (17A) and 198W/1ohm – is lifted here. I am quite sure this has been addressed by MF following our exclusive review and Lab Report! So, while the Nu-Vista 800.2 delivers the same 2x330W/8ohm and 2x580W/4ohm we saw from the PAS, it boosts this to 369W, 707W, 1.30kW and 2.20kW (47A) into 8, 4, 2 and 1ohm loads under dynamic conditions [re. 1kHz/10msec at <1% THD, see Graph 1]. Overall gain is +30.8dB which is exactly the combined gain of the PRE/PAS combination, although the A-wtd S/N ratio of 86.3dB (re. 0dBW) is still short of the 94.1dB achieved by the PAS even with the split in gain taken into account. The PAS's external PSU, and enhanced filtering, clearly exercises some advantage.

The 800.2's response is also slightly more 'rolled off' than that of the PAS, its –3dB limits of 3Hz-80kHz being inside the <1Hz to >100kHz –3dB bandwidth of the partnering power amp. Its output impedance is almost identical, however, at 0.019–0.068ohm (20Hz-20kHz), increasing to 0.58ohm/100kHz, so any modification of the 800.2's system response with different loudspeaker loads will be the same as that experienced with the PAS. The layout is necessarily more cramped inside the 800.2 so there's ~5dBV of extra residual noise plus a little extra capacitive coupling, all contributing to a slightly poorer (but not 'poor') 94-59dB stereo separation compared to the 113-93dB achieved by the PAS. How does the 800.2 compare with the original 800? See my boxout on p51. PM