Musical Fidelity Nu-Vista PAS Balanced Stereo Power Amp with Separate Power Supply (Silver)

Description

NU-VISTA PAS | POWER AMPLIFIER

The Nu-Vista PAS is a fully balanced, discrete stereo
power amplifier with separate power supply unit.

Based on our excellent Nu-Vista 800 circuit we decided to go
all out “fully balanced” on the Nu-Vista range.

The Nu-Vista PAS features the tried and tested Nu-Vista
stage featuring 6S51N nuvistors in a discrete class A amplifier buffer.

Technical Talk

This is followed by a balanced configuration circuit and
balanced input high power, low distortion output amplifier stage. The power
stage has 5 pairs of high power thermally compensated output devices for
reliable and stable operation.

Based on Titan 1000W stage, it has separate capacitors for
bulk supply, and one each for output devices con siderably reducing output
impedance and improving dynamics. Chokes are added for further improved supply
ripple and pulse current spike reduction Bias is set for over 5W of initial
class A operation thereafter the stage slides into class B operation at a point
where the now much lower discontinuity is easier dealt with than “standard”
crossover distortion.

Nu-Vista PAS Power Supply

The Nu-Vista PAS comes with its own dedicated external power
supply.

To achieve better noise performance, we removed the AC mains
power supply from the main unit and built it into another matching box. In this
box we took advantage the extra space to set up inbuilt mains and output filtering.
This quietens up the supplies and results in almost no mains-borne artefacts
getting into the sensitive audio circuitry. The Power supply has ON/ Standby
LEDs and is controlled from the main unit front panel. If total mains isolation
is required, the power supply also has rear mounted mechanical rocker switch
for full power off.

Heroic Build Quality

The Nu-Vista PAS‘s mechanical construction is
uncompromisingly rigid and solid in typical Musical Fidelity tradition. Front
panel and side panels are milled from extruded aluminium profiles and are
extremely massive.

The separate Nu-Vista PAS PSU houses all the transformers,
which by nature generate mechanical vibrations and radiate harmful
electromagnetic fields. Here they are as far away as possible from the critical
amplifier circuits. This significantly contributes to great signal to noise
ratio. We basically get immunity against the effects of vibration from the
environment. The same can be said about electro magnetic immunity. The massive
aluminium case acts as a Faraday cage. It protects the internals against outer
electromagnetic fields, and in the same way, the rest of your hi-fi gear
against electromagnetic fields generated by the Nu-Vista PAS.

The Legendary Nu-Vista Stage

Never before in the history of hi-fi have Nuvistor tubes
been coupled with state-of-the-art fully balanced and discrete technology and
sophisticated modern design techniques. The Nu-Vista PAS & Nu-Vista PAS
PSU‘s technical performances are astonishing. They measure like a dream but,
more importantly, sound incredible. Silky smooth with enormous transients and
an effortless feel that is at once relaxing and involving. Of special note how
they project images between the loudspeakers so that you can almost touch them.

The new Nu-Vista PAS and its PSU were a continued labour of
love for Musical Fidelity. We are passionate about what we do and passionate
about Nuvistor tubes as we have always been. We hope that you derive as much
pleasure listening to the Nu-Vista PAS as we had creating it.

Nuvistor Tubes

Nuvistor tubes were invented in the 1950s to solve the many
shortcomings of conventional tubes. Unlike them, Nuvistor tubes offer very high
reliability, low microphony, low noise, consistency from batch to batch, small
size, relatively low power consumption and great technical performance.

One famous application was in the Ampex MR-70, a costly
studio tape recorder whose entire electronics section was based on nuvistors.
Another limited application of this very small tube was in studio-grade
microphones from that era, the AKG/Norelco C12a, which employed the 7586, being
a good example.

It was also later found in the famed Neumann U 47 studio
microphone. This microphone was highly regarded by artists all over the world,
and was used by many top recording artists such as Frank Sinatra, The Beatles,
and so on. Remarkably, you can currently see a U47 microphone, with its stand,
cables and power supply on eBay for $10.999 „Buy-it-now“.

Unfortunately just as uses for Nuvistor tubes were being
explored, the transistor was invented and it was ‘game over’ for Nuvistors.
There the matter rested until about fifteen years ago, when Musical Fidelity
created the first of its ground-breaking Nu-Vista series. These legendary,
limited-edition products sold out in a matter of months. Today, fifteen years
later, they command very high secondhand prices because of their beautiful
sound, build quality, and longevity.

Nu-Vista PAS – Specifications

Amplifier

• High
  output power, greater than 300W into 8 ohms, 500W into 4 ohms, 1000W peaks
  into 2 ohms

• Output
  Voltage: 49 Volts RMS

• Output
  Current: 130 Amps peak to peak

• Damping
  factor: 200

• Output
  devices: 5 pairs per channel

• Gain:
  16x (23.5 dB)

• THD+N:
  < 0.003 % typical, 20Hz to 20 kHz

• Signal
  / noise ratio: >108dB ‘A’-weighted

• Channel
  separation: >96dB

• Input
  impedance: 100 k Ohms

• Input
  sensitivity for full output: 3 Volts RMS

• Frequency
  response: + 0, –1dB, 5Hz to 50 kHz

In & Output

• 4
  fully independent inputs: 2x RCA & 2x XLR

• 2 loop
  through outputs: 1x RCA & 1x XLR

• Speaker
  outputs: 2 pairs 4mm banana plug/binding posts

• Trigger
  input and output: 3.5mm mono jack socket

• Trigger
  level ±5V to ±12V

General Information

• Weight
  PAS: 27kg net (35kg)

• Weight
  PAS PSU: 40kg net (50kg)

• Dimensions
  PAS (WxHxD): 483 x 187,5 x 475 (494 with connectors)

• Dimensions
  PAS PSU (WxHxD): 483 x 187,5 x 475 (478 with connectors)

• Mains
  voltages: 115/230VAC 50/60Hz (factory pre-set); 100VAC 50/60Hz
  (alternative)

• Consumption <0.5W in standby mode; 130W on
  and idle; 1060W maximum