Интегральные усилители — Unison Research UNICO 90

Unison Research builds the UNICO 90 in Italy as a hybrid integrated amplifier, in which valves handle the input and transistors the output. The maker describes it as a Class AB design with zero global feedback that, like its more exclusive all-valve amplifiers, uses only two stages. All of the voltage gain comes from the single valve stage, so that stage defines the character of the amplifier.

Key specs that matter

Output is 100 W RMS per channel into 8 ohm and 160 W RMS per channel into 4 ohm. The rear panel carries six line inputs, namely two balanced XLR, three RCA and one RCA bypass. Input impedance is 21 kohm in parallel with 300 pF and input sensitivity is 860 mV RMS. Frequency response is -1 dB at 12 Hz and -3 dB at 45 kHz. THD is below 0.15% at 1 kHz and 1 W and below 0.5% at 1 kHz and 10 W. Output resistance is under 0.4 ohm and stays resistive across the audio band. The case measures 43.5 x 44 x 18 cm and weighs 20 kg, and consumption reaches 550 W at full power into 8 ohm.

Engineering and use context

Operating in pure Class A, the input section uses two ECC83 double triodes in totem pole configuration and four ECC81 in parallel totem pole, and this one stage both amplifies the input signal and drives the power stage directly. Only local feedback is applied. The thermally stable Class AB output stage uses complementary Hexfet devices, three pairs per channel. At switch-on an automatic warm-up phase keeps the output stages disabled while front LEDs blink. Valves reach working temperature in under 40 seconds, and Unison Research recommends about 10 minutes for best results. A thermal protection circuit shuts the power stage down if internal temperature rises too far and restarts it automatically once it cools. The manual states that valve life exceeded 1,500 hours in laboratory tests and that replacements must be the same type, matched in pairs. The supplied infrared remote adjusts volume only.

Pairing

The bypass input sends the signal straight to the main board without passing through the selector or volume control, letting the UNICO 90 act as a power amplifier within a home cinema processor chain. A volume-controlled subwoofer output provides a buffered full-range feed for an active subwoofer, and a tape output carries a buffered signal from the selected input. Doubled 4 + 4 loudspeaker binding posts suit bi-wired cable runs.

Alternatives

The Unison Research Unico Due is a hybrid integrated amplifier with two ECC83 valves, a USB input and a phono stage.