Our Verdict 
The Sinfonia is a fine amplifier that’s capable of a sparkling performance in the right system
For 
Refinement and smoothness
exceptional build and finish
Against 
Not the last word in slam
needs careful system partnering
Reviewed on

It's easy to gush about valve amplifiers, particularly when they're as seductive as Unison Research's Sinfonia. Even those with just a passing interest in hi-fi wouldn't mistake this 27 watt per channel integrated amp for anything other than a quality item.

Build is immaculate: the finish on the wooden sections is exquisite, both on the amp and remote handset. Many an established high-end company would blush with shame at the standards set by this small Italian manufacturer.

Once powered up, things get even better. The Sinfonia's quartet of KT88 valves glows brightly, and gives off a warm sheen after a few minutes of use. Rarely has central heating looked so enticing, and rarely has an amp sounded so civilised.

Sonically, the Sinfonia harks back to the traditional valve-amp stereotype of smoothness and refinement. Throw some ropey recordings at it – we used Mary J Blige's The Breakthrough – and it'll respond in cultured tones. The Sinfonia will leave no doubt as to the quality of recordings, but it'll round off the rougher edges to make your listening experience as palatable as possible.

Surprising kick Dynamics are strong, and bass has surprising kick considering the amp's limited power output. It goes without saying that sensitive, easy-to-drive speakers will work best - though, having said that, we tried everything from ATC's mighty SCM50s, to Diapason's tiny Karis, and Eclipse's unusual TD510s, without coming across a serious mismatch.

More after the break

Push the amp to high volumes with a demanding piece such as Holst's Mars, and it'll start to compress gently, and lose a grip of what is, most of the time, a taut and tuneful bass-end. Stereo imaging is pleasingly secure and focused, though, while general levels of detail resolution are as high as you would hope for at this kind of price level.

Too calm and collected Good as the Sinfonia is, it needs more bite and a greater ability to track fast-moving rhythms to be a true all-rounder. As things stand, it sounds a tad too civilised to be totally convincing – though much depends on what type of music you listen to. If you're a fan of classical or mainly easy-going vocal material, there are few better buys at this price.

Also, don't forget that this Unison Research is a thoroughly modern integrated amplifier, despite its use of Jurassic technology. The Sinfonia has a remote control, plenty of protection circuitry, and is engineered to last a lifetime.

Add all that to the seductive sound, impressive build and the alluring glow of valves, and you have one alluring product.