British tube-amp maker Icon Audio brought a couple of variations on an existing theme to Whittlebury. The Stereo 40-6AS7 (£1400) is a pure-triode version of Icon’s Stereo 40, which uses KT88 or EL34 tubes and runs in triode or ultralinear mode. The 6AS7 military valve is capable of 33 watts, and Icon's David Shaw explained that its relative obscurity is due to there being no substitute tubes. Those after a more delicate sound might be interested in the Stereo 40-2A3 (£1700) with a 17-watt output and a sound that comes very close to the 300B model at a far lower price.