Интегральные усилители — Musical Fidelity Nu-Vista 600.2

The Nu-Vista 600.2 is a fully analogue, dual mono integrated amplifier from Musical Fidelity that uses nuvistor tubes together with Class A circuitry. Four 6S51N nuvistors, two per side, form a discrete Class A buffer stage in the preamplifier section. Nuvistors were mass produced in the late 50s and early 60s and were adopted for their small size and durability. Its chassis platform comes from the Nu-Vista 800.2 and is aimed at smaller rooms. The US list price was USD 9,999.

Key specs that matter

Rated power is 160 W per channel into 8 ohms and 300 W into 4 ohms, with 500 W peaks into 2 ohms. Maximum output voltage is 36 V RMS and maximum output current is 50 A peak to peak. Frequency response runs from 10 Hz to 30 kHz within plus 0 and minus 0.1 dB, THD plus noise is below 0.005 percent typical from 20 Hz to 20 kHz, and signal to noise exceeds 107 dB A-weighted. Damping factor is 100. The amplifier is 483 x 187 x 510 mm, weighs 36 kg net or 44.3 kg boxed, and draws up to 600 W.

Engineering and use context

The pre-amplifier and nuvistor stages are fully independent for each channel, each with its own power supply, and a newly designed circuit board places the nuvistor stage on a self-screening tray above the main circuitry. The output section, described as a V4 engine, uses four output transistors per channel operating in Class AB. Its design mirrors the brand's TITAN amplifier, with each transistor coupled to its own high-current bulk supply capacitor for immediate access to energy and lower signal path impedance. Output stages are separately buffered to prevent cross-interference. Milled aluminium front and side panels shield the internal circuitry as a Faraday cage. Volume uses a laser-trimmed control with plus or minus 0.5 dB gain precision, the display shows input, volume or live VU meters, and an aluminium remote handset is included.

Pairing

Inputs are four RCA pairs and two balanced XLR pairs, with 100 kohm input impedance. Outputs include fixed and variable RCA pairs plus fixed and variable balanced XLR pairs, so a subwoofer, second power amplifier or recorder can be connected. The design is fully analogue, so digital sources need an external DAC and vinyl playback requires an outboard phono stage.

Alternatives

The Musical Fidelity Nu-Vista 800.2 is the more powerful nuvistor integrated of the pair, with 330 W per channel into 8 ohms.