Integrated amplifiers — Unison Research UNICO PRIMO

The Unico Primo is a stereo integrated amplifier from Unison Research, which is located at Dosson di Casier close to Treviso in Italy. The model is part of the Unico series and follows the hybrid recipe of that family, with a valve in the input section and MOSFET transistors in the output section. Unison Research describes it as a small amplifier that carries over technology from its more expensive designs, and it lists solid construction, careful selection of components and precise assembly as part of an almost artisan approach that reflects its Treviso origins.

Key specs that matter

Each channel delivers more than 80 W according to the maker. The output stage uses four power MOSFETs biased in what the company calls dynamic Class A, and the input stage runs as a triode in Class A around a single ECC83 valve. Input sensitivity is 260 mV with an input impedance of 50 kohm in parallel with 47 pF. Frequency response is quoted as -0.1 dB at 10 Hz and -0.5 dB at 100 kHz. Negative feedback is set at 10 dB and the damping factor exceeds 50. Maximum power draw reaches 380 W. The chassis measures 43.5 cm wide, 43 cm deep and 9.5 cm high, and the net weight is 14 kg.

Engineering and use context

The rear panel offers five RCA line inputs plus a tape input, and one of the five positions can be fitted with an optional phono board. Outputs include a tape feed and an RCA subwoofer output. Loading on the optional phono board is 47 kohm with 220 pF for MM pickups and 100 ohm with 440 pF for MC pickups. Its base gain is 40 dB for MM and 50 dB for MC, and a selector adds either 0 dB or 10 dB on top. Maximum input voltage on the MM side is 120 mV at 1 kHz. The RIAA network is partly active, handling the bass region, and partly passive for the treble, and distortion of the phono board is 0.09% with a 5 mV MM input at 1 kHz.

Pairing

With the phono board installed, a record player plugs directly into the amplifier whichever of the two cartridge types it carries, while the remaining inputs take line-level players. Because the board is optional, a buyer without a turntable can keep all five RCA positions for line sources. The tape loop allows a recorder to be connected, and the subwoofer output gives a direct route to an active subwoofer.

Alternatives

In the same Unico series Unison Research offers the Unico Nuovo, a hybrid integrated rated at 95 W with an eight-MOSFET output stage and two ECC83 valves.