MEASUREMENTS

I measured the Krell K-300i using my Audio Precision SYS2722 system (see the January 2008 “As We See It”). I usually precondition amplifiers by running them at one-third power into 8 ohms for an hour. The Krell almost made it, turning itself off after 55 minutes, with the front-panel display showing the message “Over temperature left channel.” The top panel over the heatsinks was hot, at 142.8°F (61.6°C), but cooler over the transformer at 113.1°F (45.1°C). This is a tough test for an amplifier with a class-AB output stage, as one-third power results in the maximum dissipation in the output devices. The Krell has just sufficient heatsinking for its power rating but should be given plenty of space for ventilation.