The Unico 100 integrated amplifier is quite a beast, it weighs a formidable 25 kilos and delivers a respectable 180 watts from each of its dual mono channels.

It does so without looking overly bulky, so it's an even greater shock when you first attempt to move it.

As the power output would suggest, the second half of the amplifier is the transistorised one, where three pairs of Mosfets are gathered in a parallel configuration (possibly as a result of its valve roots, Unison prefers to use multiple low- power devices rather than a few big ones).

Controlled performance

The preamplifier section is a double triode stage utilising a single ECC83/12AX7 valve, with special attention being given to the interface between glass and silicon.

Here Unison says it has used a topology that ensures regulation of the DC component of the signal without compromising performance at low frequencies. The digital volume control consists of an integrated circuit that uses an array of precision resistors combined with digitally controlled analogue switches.

The output level is indicated on the front panel display and has 99 steps that start at 0.0 and rise to 9.9. We found that even with the quietest discs and reasonably sensitive speakers, the numerical level never exceeded 2.5 and was usually in the 1.8 to 2.2 range.

This number is, of course, fairly abstract, but it would be more satisfactory if the control had been 'geared' so that you could at least approach 9.9.

Amp design

Switching it on elicits a 30 second countdown via the display, while the amplifier stabilises voltages. It takes somewhat longer to actually warm up, but produces plenty of heat when it's truly ready to play.

The two large fascia-mounted dials control volume and input selection, both also serve a function when pressed (mute and tape loop). Volume can also be adjusted with the system remote, a device that's largely hewn from solid wood and stands up like a cordless phone.

Connections consist of four single-ended and one balanced input, alongside tape and volume controlled sub outputs. These are in a mirrored arrangement that defies guesswork when attempting to hook it up in a dimly lit space!

Speaker terminals are doubled up for ease of bi-wiring and the casework is entirely aluminium which is very nicely executed and seldom seen at this price point.

Lively combo

Having manhandled this beast into a Custom Design Icon rack, we connected it up to a pair of PMC OB1i speakers that had been giving great service with another amplifier.

The combination is a lively one, perhaps too lively through the midband, this being an area where both components excel. And while the pairing is extremely open and well timed, it can get a little bit too forthright.

Bass lines are very clear cut with reasonable weight, but instruments nearer the midband are a little bit obvious in the mix. It's nice to hear all the air around them, but not if it starts to mask the lead voice in the music.

Strong timing

Switching over to a Leema Tucana integrated (around the same price), makes this imbalance more obvious with a more powerful and better timed result that seems rather more tonally even.

Conversely it does highlight the openness of the Unico 100 which is, undoubtedly, a reflection of the valve content of its preamp section. These may also help the timing, which although is not quite in the Tucana league is better than usual, something which enhances the enjoyment of all manner of music.