As we headed towards the twilight years of the thermionic emission device in the late 1950s, a last ditch attempt at building an ultra-reliable vacuum tube, exhibiting the very best measured performance without the inherent glass-based microphony, led to the development of the metal-cased nuvistor valve. This almost indestructible low-distortion device was used mainly in televisions throughout the 1960s, but changing technologies in the 1970s saw the little metal wonder’s reign come sadly to an end. Small quantities were used in high quality recording studio gear, but in general terms the nuvistor valve’s fire was extinguished.
Then, towards the end of the last century, Musical Fidelity’s founder Antony Michaelson saw the opportunity of utilising this super-valve in thoroughly modern audio amplification. He purchased all the nuvistor valves he could get his hands on.
This coup led to the first generation of ‘Nu-Vista’ products — and several subsequent ones — that were feverishly sought by enthusiasts after a collection of ‘glowing’ reviews from around the world. But according to Michaelson, although he had plenty of nuvistor valves at hand, he was short of the necessary valve bases. One will not work without the other, of course. That led to the Nu-Vista range being phased out, Musical Fidelity continuing with more conventional circuitry designs for on-going offerings. But then another coup. Internet enquiries led Michaelson to a lost stash of the elusive nuvistor bases — and he proceeded to acquire the entire lot. Thus the Nu-Vista designs have been reborn, with the recently-launched Nu-Vista 800 being the integrated flagship, and the subject of this review.
Old leads to new
Musical Fidelity’s top-level kit has always been anything but boring. The well-engineered designs are enhanced by all manner of chassis embellishment from gold panel accenting to oversized control knobs — even, on one recent design, component feet that lit up in kaleidoscopic colours to indicate the amp’s status... Until recently, this writer owned that glorious two-box kW 500 integrated, also featuring nuvistor valves, and kW 750 power amplifiers, and misses both the colourful show as part of the warm-up cycle and the superb audio quality. In fact, many enthusiasts consider these two among the best the company ever made. So can the nuvistor newbie live up to the rep?
The Nu-Vista 800 was delivered safely in a double box with further protection provided by stiff foam inserts, the unit itself in a scratch-protecting soft velvet bag. Further niceties include cotton gloves, which will prevent ring scratches when unpacking, and a signed letter from Antony Michaelson to pre-warm the cockles and reassure the purchaser.
The Nu-Vista 800 itself is a beastly impressive bit of kit. High grade and large gauge aluminium panels are highlighted with immaculate etching of model number (front fascia) and company name (top panel front). Two large knobs either side of a central display provide a symmetrically-balanced face with the only other buttonry being standby/on and display on/off switches, along with a small infrared receiver window. The top panel is a heavy aluminium plate with meshed window cut-outs allow for cooling, while horizontal heatsinking spans the sides. The amp runs moderately warm while in operation.
A small cardboard box contains the Nu-Vista 800’s accessories which include, as options for the unit’s feet, a choice of well-made milled aluminium spikes (complete with surface-protecting discs) or felt pads. A rather large and attractive solid aluminium remote control is included and is provided with little stick-on rubber feet, batteries and a Philips-head screwdriver for access to the battery panel. I should stress here that the overall design, build quality, fit and finish and attention to construction detail is superb, on par with the best in the business.
The Nu-Vista amplifier has been quoted as being capable of providing 300 watts per channel into 8 ohms. It’s a high current design with one massive 1.5kVA toroidal transformer per channel and a large capacitor storage bank visible through the top panel vents (the substantial 40kg weight confirms the heavy iron content). Five pairs of bipolar output devices per channel are used, while the amp’s current capabilities are said to top 120 amps peak to peak. It’s a very low distortion amplifier; Musical Fidelity quotes 0.005 percent total harmonic distortion plus noise across the 20Hz to 20kHz range. Input impedance is quoted as being 40kohms while the damping factor is actually 200 which, in conjunction with the high current capabilities, should provide good control of demanding woofers in low impedance speaker designs.
Around the back, within a copper-coloured sub-panel, you’ll find suitable connectivity options (all with high quality socketry) starting with four unbalanced RCA line inputs (auxiliary 1 is switchable to cater for home theatre applications), a balanced XLR input, and an unbalanced RCA preamp-out which allows the use of the nuvistor preamp stage with an external power amplifier. Twin good quality speaker binding posts for easy bi-wiring while an IEC socket allows for aftermarket power lead experimentation.
Musical Fidelity’s penchant for ambience lighting is still in play here. The Nu-Vista 800 features a bank of down-shining bright green LEDs in its underbelly which will bathe your rack or stand in sunny luminosity. A small gridded opening on the top panel displays the four nuvistor valves, each featuring an LED ring of their own, in orange at start-up, then turning to green when the amp has reached its optimal operating temperature — this illuminated group arrangement actually looks great. A variety of lighting combinations — including all LEDs and the display off — are switchable via the unit itself or the remote control.
In our room the Nu-Vista 800 projected one of the widest soundstages we’ve had the pleasure of being immersed in. This massive soundfield also created the illusion of majesty and scale, where
orchestral pieces, in particular, sounded spatially and also dynamically substantial. The amplifier sounded like it had endless power in reserve, as you might expect with that 300-watt rating and massive power supply — but more surprising was the ability of the Nu-Vista 800 to often jolt me with a musical transient that, unexpectedly, shot clean out of the mix. A pulled guitar string or a sudden tom hit could become a thrilling experience with this amp. Demanding high amplitude attacks are a piece of cake here — this amplifier has an enormous dynamic capacity. And we’ve had plenty of powerful amps in situ, some even more so, most notably the Nu-Vista 800’s older brother the kW 750 mentioned above — itself a 750-watt powerhouse — but the way the Nu-Vista 800 handled transient pulses surpassed it. As essential as ample power and ultimate dynamic ability are in terms of conveying musical realism, those attributes make for an amalgam of qualities the Nu-Vista 800 is capable of. No matter the material, be it of audiophile-level standards or guilty pleasures suffering poor production, the 800 (for short) displayed a supremely refined demeanour. Highs were extremely delicate, extended and detailed while the midrange’s considerable resolution never crossed the line into brashness.
The enormous soundstage recreated here allows images to spread and individualise in all the perspectives; there’s a sense of gravitas to the music that commands the listener’s attention. This sonic weight is aided by the 800’s command of the low registers. Our speakers are a tough impedance load, in the 80Hz-100Hz range especially, but the 800 just held tight. No matter the bass content the amp reproduced it with phenomenal depth, punch, detail and rhythmic flow. And again, those scary transient attacks provided an entertaining and exciting factor to well-recorded rock.
Throughout the auditioning period of some weeks, not once did the 800 disappoint when it came to music-making. The stereotypical solid state spectres of congestion and brashness in the midrange were never raised. This is a high-powered behemoth with a dollop of sweetness that does not take away from the musical detail and overall dynamic expression.
Over-sibilant recordings — I have a few of those which are used expressly for testing but which I also enjoy on a content level — especially of female singers, were well-controlled via the 800. The fundamental ‘sss’ sound was still there but it did not grate, or even hurt, as it can with other components I’ve experienced.
The amp treads a fine line between sweetness and a realistically detailed presentation. That’s the mark of a skilled engineering team which no doubt spent as many or more hours listening as they did measuring.
The Nu-Vista 800 falls in line with some of the classic Musical Fidelity integrated amplifiers of years past — big, well-built and thoroughly-designed powerhouses. This new offering, however, takes the concept of a big integrated to a new level of build quality, excellence in engineering and overall performance. With a style reminiscent of the company’s biggest-ever power amp, the Titan, and the equal of that masterpiece’s level of fit and finish, the Nu-Vista 800 throws the gauntlet to top-level preamp/power amplifier separates. Musical Fidelity may just have itself yet another integrated classic for the ages…
Valve: 4 × Nuvistor
Power output: 330 watts per channel into 8 ohms
Current capacity: 200 amps peak to peak
THD (+ noise): <0.005 percent typical (20Hz-20kHz)
Signal to Noise Ratio: >107dB A-weighted
Frequency Response: 10Hz-30kHz (+0, –0.1dB)
Line-Level Inputs: 4 × RCA phono pairs,
1 × line level XLR balanced pair
Line-Level Outputs: 1 pair line-level RCA connectors (constant level), 1 × pair line-level RCA connectors (preamp outputs)
Dimensions (WHD): 483 × 187 (212 on included optional pointed feet) × 510mm
Warranty: 24 months