I went out and measure, and that seems very low putting the steps only a couple inches above the ground. I spoke to AMP today and they said the steps drop 13" from the bottom of the door sill. I am trying to determine the difference between where the factory steps height vs the AMP power step. I didn't test the Musical Fidelity's clipping power into 2 ohms, as the amplifier isn't specified as being able to deliver full power into 2 ohms except on peaks (footnote 1).HI, and thanks in advance. However, the wall voltage had dropped to 115.9V AC with the amplifier clipping into 4 ohms. (I don't have a sufficiently powerful Variac to hold the wall voltage constant in my amplifier testing.) Into 4 ohms with both channels driven, the Nu-Vista 800.2 clipped at 470Wpc (23.7dBW, fig.5) compared with the specified 500W (24dBW). Fig.4 indicates that the amplifier clips at 290Wpc into 8 ohms (24.6dBW), though it's fair to note that the supply voltage had dropped from 119V AC with the amplifier quiescent to 116.5V AC when both channels were clipping into 8 ohms. At our usual definition of clipping, which is when the THD+N reaches 1%, the Nu-Vista 800.2 didn't quite meet its specified output power of 330W into 8 ohms (25.2dBW). The downward slope below 30Wpc into 8 ohms and 60Wpc into 4 ohms indicates that the distortion lies below the noise up to these powers, but it remains low until the actual onset of clipping. These will be due to magnetic interference from the two massive power transformers, but are all very low in level.įig.5 Musical Fidelity Nu-Vista 800.2, distortion (%) vs 1kHz continuous output power into 4 ohms.įigs.4 and 5 respectively plot how the THD+noise percentage varies with output power with both channels driven into 8 ohms and 4 ohms. Reducing the volume by 20dB and increasing the input signal by the same 20dB so that the output power remains at 1W drops the random noisefloor by 9dB (green and gray traces) and unmasks some odd-order harmonics of the AC supply frequency. The blue and red traces in fig.3 show the amplifier's low-frequency noisefloor at 1Wpc into 8 ohms with the volume control set to its maximum. 1W into 8 ohms is equivalent to 105.2dB ref. full power into 8 ohms, as my 80.2dBA ref. Musical Fidelity specifies the amplifier's A-weighted S/N ratio as >107dB. This ratio improved to 77.6dB when the measurement bandwidth was restricted to the audioband, and to 80.2dB when A-weighted. 2.83V, which is equivalent to 1W into 8 ohms. The wideband, unweighted signal/noise ratio, taken with the unbalanced CD input shorted and the volume control set to its maximum, was superior to that of the original NuVista 800, at 69.5dB in both channels, this ratio ref. The balanced input impedance was the same as I found with the original Nu-Vista 800, at 18k ohms across the audioband.įig.3 Musical Fidelity Nu-Vista 800.2, spectrum of 1kHz sinewave, DC≡kHz, at 1Wpc into 8 ohms with volume control set to the maximum (left channel blue, right red), and to ≢0dB (left green, right gray) (linear frequency scale).Ĭhannel separation below 2kHz was superb, at >100dB RL, >90dB LR, and still 77B in both directions at 20kHz. I measured 46k ohms at 20Hz, 41k ohms at 1kHz, and 17k ohms at 20kHz for the unbalanced inputs. The input impedance is specified as 40k ohms. The Nu-Vista 800.2 preserved absolute polarity for both balanced and unbalanced inputs, its XLRs being wired with pin 2 hot. At the maximum volume control setting of "7.0dB," the voltage gain at 1kHz into 8 ohms was relatively low for an integrated amplifier, at 30.6dB for the unbalanced "CD" input and 30.8dB for the balanced input. The Nu-Vista 800.2's volume control operated in accurate 0.5dB steps. Following that period, the top panel was warm, at 100.1☏ (37.9☌), and the side-mounted heatsinks hotter, at 130.1☏ (54.5☌). As the amplifier is specified as having a maximum output power of 330Wpc into 8 ohms, I preconditioned it before the measurements by following the CEA's recommendation of running it at one-eighth that power into 8 ohms for 30 minutes. I performed a full set of measurements on the Musical Fidelity Nu-Vista 800.21 using my Audio Precision SYS2722 system.
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