Our Verdict 
Valve amps might not be as popular as they once were, but the Preludio is a fantastic example of the genre
For 
Quirky appearance
sweet sounding treble
expressive and emotional midrange
detailed across the board
Against 
Fussy about speakers
looks won’t impress everyone
Reviewed on

Locking eyes with a valve amp is a bit like seeing a friend's newborn baby for the first time: some people are smitten and can see a place for one in their life, while others scream and run to the nearest exit.

But, love them or hate them, there's a lot to be said in favour of valve amps, and in particular the Unison Research Preludio.

The mixture of stainless steel and striking cherry wood, the smooth control knobs and the side-mounted heatsinks give this amp plenty of character.

The Preludio only outputs 14W per channel, so you need to make sure its partnering speakers are compatible and can be driven to their full potential (ideally they should have a sensitivity rating of at least 90dB).

Listening to the Preludio from cold, the presentation is closed-in and stifled, but it's surprising how the soundstage opens up as the valves hit their optimum working temperature.

More after the break

Bass notes to Jay-Z's Run This Town have a much more convincing kick to them and there's a real dynamism and newly injected freedom as far as the flow of the track is concerned.

Bags of character in the midrange Rhianna's vocal on the track is sweet and refined, her distinctive tone oozing character. The sweet, smooth-sounding treble and midrange never gives even a hint of hardness.

This honesty and integrity gives the Preludio a real star quality. It's a remarkably easy listen, but not in a dull or forgettable way.

Play 160 BPM, and the Preludio allows the percussion to sparkle in a manner that comparable amps struggle to match.

Spin another classical track such as John Williams' Theme To Jurassic Park and the Preludio steps up to the plate once again, producing an intimate, emotive sound.

There's no doubt the Preludio sounds like a classy piece of kit, and it thoroughly deserves its five-star rating.

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