A few years ago, Krell stood at something of a crossroads. There had been a public and somewhat acrimonious split between the company founder and its new owners, and the ideas behind the brand were looking a little old-fashioned. It could have quietly sunk below the radar. Instead, we’re looking at Krell 2.0, at nu‑Krell, and the Vanguard integrated amplifier is exactly as its name suggests; leading that charge into the future of audio.
There’s a problem with change, though. It’s tempting for a company to throw the baby out with the bathwater. Change is good, but change for change’s sake isn’t. Fortunately, the Keepers of Krell decided to keep what is good, and only change what is needed to change, in part to keep abreast of 21st Century developments.
This means the amp is a blend of tried and trusted, and state-of-the-art. The tried-and-trusted part is all about the audio performance, with a Class A preamp, coupled to a beefy ‘iBias’ style power amplifier stage delivering 200W per channel into eight ohms, and doubling that load to 400W into four ohms. This is made possible thanks to a heavy 750VA toroidal transformer on one side of the chassis, and a healthy 80,000µF of reservoir capacitance, and noiseless fan-cooled heatsinks on the other.
Krell’s power amp stage is perhaps best described as a ‘sliding bias Class A’ design. The circuit continuously monitors the output stage, adjusting the bias on the fly instantaneously to accommodate the demands put upon it by the loudspeaker load. In theory at least, this means the Vanguard, and all its iDrive power amplifier bigger brothers, should be capable of delivering a performance without the crossover distortion inherent to any amplifier class that isn’t Class A, but without the ecologicially-challenging inefficiency that is entailed with those designs. Or, put simply, Class A sound without Class A heat and fuel bills. Vanguard doesn’t get much more than pleasantly warm in use, but the chassis bristles with ventilation holes all the same.