Cambridge Audio Azur 651A Amplifier

This fi ne-looking integrated presses all the right audiophile buttons, so to speak. The company has form as a purveyor of no-frills hi-fi equipment for a small amount of money. The 651A is a relatively substantial product by the standards of this group - although it isn't alone in having a slightly flimsy pressed steel top plate. The front fascia is a lovely chunk of brushed aluminium, way nicer than the company was offering just a few years ago. It's crowded with bass, treble, balance and volume controls, plus input selection and a front 3.5mm 'MP3' socket. It offers six inputs including USB (digital) and MM phono.

Inside there's a largish toroidal mains transformer, which makes for a strong power supply to underpin its claimed 75W RMS output power. Separate transformer taps for left and right channels are provided, as are twin rectifiers and separate rails for the left and right power amplifier sections - these feature proven Sanken output transistors (STD03N/STD03P) running in Class AB mode. A 'high-grade film type' volume potentiometer is fitted, and Cambridge Audio's CAP5 protection system saves your speakers should overloads, faults and/or clipping occur. The built-in DAC runs USB 1.0 up to 16-bit/48kHz resolution, meaning that it won't be able to play out high-resolution music from a computer.

Off to a good start, fundamentally, this amplifier sounds right. It simply has no weak areas, and has various strong ones that frankly you wouldn't expect at this end of the market. Bass is a little lighter than you'd get from an integrated at twice the price, but is par for the course here, and what there is, is nicely fluid and bouncy. It powers the song along in an enjoyable and unselfconscious way, and blends well into an open and textured midband by the admittedly undistinguished standards of the group. This then pushes up to a decently airy and smooth treble, the result being a budget amplifier that sounds anything but.

For example, the Kraftwerk track has one of the most impressive rhythmic sounds here, with wonderful insight into what the band's two drummers (or 'electronic percussionists' as they prefer to call themselves) were doing together. Compared to the Vieta VH-HA100 for example, there is a whole extra layer of detail to the song's rhythms. At the same time, texturally the Cambridge Audio Azur 651A is excellent. Again, it sounds far more tonally natural than the others reviewed here. It makes every other amp sound rather misty, foggy, opaque or processed. This is obvious whatever music is used via the analogue inputs - the Fun Lovin' Criminals and Squeeze tracks are radically different recordings and it tells you so, whereas others like the Pioneer A-50 don't. The 651A also goes surprisingly loud very confidently too, keeping its spacious soundstage, decent depth perspective and positive stereo imaging right up to high levels. The USB input is surprisingly decent, but is still aimed at upgrading the terrible DACs inside computers rather than standing in for serious hi-fi designs. Overall then, the Azur 651A can count itself as something of a star.