The azur 840A is the most flexible, most powerful, and best-sounding integrated amplifier that the British firm Cambridge Audio has ever built, and it even introduces a new Class XD mode of amplifier operation (see the sidebar). What is more, it also serves as a “multizone” integrated amplifier, providing dual A-BUS interfaces that can send audio signals via CAT5 wiring to two remote listening zones within the house. The 840A puts out a feisty 120 Wpc, and sells for $1499.
The azur 840A incorporates numerous detail touches that purists will appreciate. For example, the amplifier provides separate power supplies for its preamplifier and power amplifier sections, and offers eight user-nameable analog inputs—including one that supports both single-ended (RCA) and balanced (XLR) input jacks. Any of the amplifier’s inputs can be locked to fixed gain levels, making the Cambridge ideal for home theater pass-through applications. Switch-selectable balance and tone controls are provided, as is a front panel-mounted Direct control that ensures the purest signal path possible. Finally, to complement its low-distortion circuitry, the 840A controls volume levels via a relay-controlled, precision matched resistor ladder. Over time, I’ve heard many British integrated amplifiers that fit the stereotype of sounding warm, softly focused, and polite. The 840A is not among them. Right out of the box, it exhibited a big, bold sound characterized by terrific midrange definition and detail, and clean, powerful bass. Where competing amplifiers such as the excellent YBA Designs YA201 featured in TPV 73 can sound a bit like contemplative sonic introverts, the ebullient Cambridge puts its lively, engaging sound right out in the open for all to hear. In short, the reasonably priced 840A signals from the outset that it wants to play with the big boys. And in many ways it can.
One important way in which the 840A plays above its pay grade is in carving the leading edges of transients with the sort of energy and definition normally associated with more expensive amplifiers. A multi-faceted musical example will help illustrate this point. I put on Long John Hunter’s “Let’s Set the Time” from the Untapped Blues Festival 2004 Live album [Bluestopia], and I came away marveling at how energetic and alive the 840A made Hunter and his band sound. If you enjoy listening to (or playing) electric guitar at moderate volume levels, then you already know how sound seems to erupt from guitar amplifiers a split second after the pick sweeps past the guitar strings. In fact, some notes launch so hard that you expect them to become unpleasantly loud. But when recording and playback levels are set just right, the individual notes instead cry out with visceral authority, yet without reaching painful levels. This punchy, evocative sound is exactly what the 840A achieved in reproducing Hunter’s guitar solos on “Let’s Set the Time.”