Integrated Amp Reviews

I first met Musical Fidelity's founder, Antony Michaelson, in 1978, when he was running tube amplifier manufacturer Michaelson & Austin. I still have an M&A TVA-10 amplifier, which was designed by the late, great Tim de Paravicini. Soon after Antony founded Musical Fidelity in 1982, he employed de Paravicini to design the A1 integrated amplifier (footnote 1).

The A1 was a slim solid state design with a class-A output stage that output 20Wpc into 8 ohms. By contrast, the massive, dual-mono Musical Fidelity Nu-Vista 800 integrated amplifier, which Michael Fremer reviewed for Stereophile in November 2015, featured nuvistor tubes for its small-signal circuitry, coupled with a solid state, class-AB output stage that could deliver 330Wpc into 8 ohms.

In 2017, Michaelson decided to retire. In May 2018, the Musical Fidelity brand and its intellectual property were acquired by Heinz Lichtenegger of Austrian company Audio Tuning. (Lichtenegger is the owner of Pro-Ject Audio Systems.)

The New Nu-Vista 800.2
When the original Nu-Vista 800's "retro-look," front-panel green-LED display was discontinued, rather than discontinue the amplifier, Musical Fidelity decided to substitute a new front panel with a larger display. They took advantage of the opportunity to make some other changes: New, rewound power transformers—one for each channel in this dual-mono design—are said to lower the noisefloor. The power supply was revised. The hefty aluminum remote control now allows the amplifier to be placed into standby mode, something that previously could only be done from the front panel; and the Display button on the front panel is now accompanied by a Display Mode button (see later).

The 800.2 still uses nuvistors for its input stages, a pair of 7586s for each channel. As MF described in his 2015 review, a nuvistor is a miniature, small-signal vacuum tube housed in a metal and ceramic case (rather than the usual glass bulb; footnote 2), said to be good for 100,000 hours of use. The nuvistor was introduced by RCA in 1959 for use in TV sets, and although it was replaced by solid state devices in mainstream uses, it appears to be widely available on eBay. I understand that Musical Fidelity has stockpiled sufficient nuvistors for its long-term use.

The Nu-Vista 800.2's specified maximum power is the same as that of the original: 330Wpc into 8 ohms (25.2dBW), 500Wpc into 4 ohms (24dBW), and 1000W peak into 2 ohms (24dBW). The output stages each still use five pairs of complementary Sanken bipolar transistors, with a supply capacitor mounted adjacent to each device to allow more immediate access to stored energy and reduce the amplifier's source impedance.

The input complement is still the same as on the 2015 amplifier: one balanced line-level pair on XLR and four single-ended line-level pairs on RCA. The RCA inputs are labeled CD, Tuner, Aux2, and Aux/HT. A rear-panel switch allows the volume control to be bypassed with the last input, for home theater use. Loudspeaker connection is with two widely spaced pairs of binding posts for each channel. There are also fixed-level and variable-level preamplifier outputs on RCA connectors.

The new display dominates the 800.2's appearance. Four themes are user-selectable with the front-panel buttons or remote control: a pair of large, white-on-black VU-style meters with blue needles, below which are the input in use and the volume setting; the same but with black-on-white meters; just the input in use and volume setting in black on a white background; and the same in white on a black background. Each of these themes can be permanently illuminated, with the brightness adjusted with the front-panel buttons, or set to turn off after a short time with a "Screensaver" mode. The amplifier's bottom-firing lights and those that illuminate the nuvistor sockets (visible through an opening at the rear of the top panel) can also be turned on or off. When they are on, they light up red when the amplifier is first powered up or the volume is muted, switching to orange when the amplifier is ready to be used or the mute is lifted.

Setup
Because of the Nu-Vista 800.2's bulk—it weighs more than 90lb—I set the amplifier up on a small, wheeled dolly so that I could move it between the listening room and my test lab as necessary. For my auditioning, I positioned the dolly midway between the Monitor Audio Platinum 300 3G floorstanding speakers I reviewed in the November issue. The speakers were single-wired with AudioQuest Robin Hood cables. Source components were either an Ayre C-5xe^MP universal disc player or an MBL N31 CD player/DAC, connected to the Musical Fidelity with 3m Ayre/Cardas balanced interconnects. I used my Roon Nucleus+ server to send network data to the MBL, controlling playback with the Roon app on an iPad mini.

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Footnote 1: An updated A1 was released in 2023; see musicalfidelity.com/products/a1/a1-2

Footnote 2: See r-type.org/articles/art-150.htm and r-type.org/exhib/aaa0274.htm.