Интегральные усилители — Unison Research UNICO 150

The UNICO 150 is an integrated amplifier in the current Unico series from Unison Research, the Italian maker known mainly for valve amplification. Like the rest of the Unico family, it is a hybrid design - valves handle voltage gain, while transistors deliver current to the loudspeakers. The maker says the amplifier was designed to suit both high-end audiophile and strictly scientific criteria, and its circuit uses only three amplification stages.

Key specs that matter

Unison Research rates the output at 150 W RMS per channel into 8 ohm and 250 W per channel into 4 ohm. Distortion is below 0.005 percent at 1 kHz and 1 W, below 0.002 percent at 10 W and below 0.003 percent at 100 W. The response is 1 dB down at 12 Hz and 45 kHz, and 3 dB down at 6 Hz and 80 kHz. Output resistance stays under 0.4 ohm and is resistive across the audio band. Six line inputs are fitted - three unbalanced RCA, two balanced XLR and one unbalanced bypass input. Input impedance is 24 kOhm in parallel with 100 pF, and sensitivity is 860 mV RMS. The casework measures 43.5 x 18 x 44 cm and weighs 25 kg, and maximum power draw at full 8 ohm output is 550 W.

Engineering and use context

A pure Class A totem-pole circuit forms the input stage, built around a double triode ECC83, while the driver stage uses the same Class A totem-pole topology with a 6H30 double triode, so four valves are installed in total, two of each type. The output stage runs in thermally stable Class AB with eight Hexfet devices. Unison Research applies no global negative feedback at all, relying instead on 16 dB of local feedback within the stages. The bypass input sends a signal straight past the volume control, which lets the UNICO 150 act as a fixed-gain power stage inside a multichannel system or behind an external preamplifier. A tape output provides a fixed feed for a recorder, while the subwoofer output follows the volume setting.

Pairing

Four pairs of binding posts, two per channel, are provided for bi-wired loudspeakers. The low output resistance and the higher output into lower loads point to loudspeakers of moderate sensitivity and lower impedance, and the volume-controlled subwoofer output makes adding an active subwoofer straightforward.

Alternatives

The Unison Research Unico Nuovo is the smaller hybrid integrated in the same series, rated at 95 W per channel with two ECC83 valves in a parallel Class A input stage and eight power MOSFETs at the output.