Integrated amplifiers — Unison Research UNICO NUOVO

Made by Unison Research in Italy, the UNICO NUOVO is an integrated design combining two valves in the input section with a transistor power stage. Unison Research calls it a fresh version of a long-running and popular model, developed from years of experiments since the Act integrated amplifier, and states that it was designed to combine high performance with an affordable price.

Key specs that matter

Five RCA line inputs are fitted, one of which can be converted to phono with the optional board. Input sensitivity is 260 mV RMS. Frequency response is -0.1 dB at 10 Hz and -0.5 dB at 100 kHz, the feedback factor is 10 dB and THD is 0.15% at 1 kHz and 10 W. Line outputs are a tape output and a volume-controlled subwoofer output. The case is 43.5 cm wide and 43 cm deep.

Engineering and use context

Two ECC83 (12AX7) double triodes work in parallel in a pure Class A input section. The output stage is biased in dynamic Class A and uses eight power MOSFETs in complementary pairs. Doubled binding posts, 4 + 4 in total, accept bi-wired speaker cables. At switch-on an automatic start-up phase of about 30 seconds disables the output stages while the front LEDs blink quickly, and the valves reach working temperature in that time. Unison Research recommends about 10 minutes for best results. Slow blinking LEDs signal that thermal protection has switched off the power stage, which restarts on its own once the inside has cooled. After even a very short mains interruption the amplifier repeats its start-up sequence. The manual gives a valve life of more than 1,500 hours in laboratory tests and asks for replacement valves in matched pairs of the same type. The infrared remote, powered by a CR2032 lithium cell, adjusts volume only. Each unit leaves the factory wired for the mains supply of its destination country, and the owner cannot alter that setting.

Pairing

The optional phono board has two active gain stages per channel and RIAA equalisation that is active at low frequencies and passive at high frequencies. It accepts MM cartridges at 47 kohm and 220 pF or MC at 100 ohm and 440 pF, with gain of 40 dB or 50 dB and 120 mV maximum input at 1 kHz. Internal links raise gain by 10 dB, which the manual advises for MM cartridges below 4 mV and MC below 0.5 mV. Phono THD is 0.09% at 5 mV and 1 kHz with MM. A rear ground connection is provided for a record player earth wire.

Alternatives

Another Unico range integrated from Unison Research is the Unico 90, rated at 100 W per channel into 8 ohm, with two balanced XLR inputs and a bypass input.