 Specifically designed for audio amplification, the KT88 has similar ratings to the American 6550 which was designed for use as a servo amplifier.It is one of the largest tubes in its class and can handle significantly higher plate voltages than similar tubes, up to 800 volts.A KT88 push-pull pair in class AB1 fixed bias is capable of 100 watts of output with 2.5% total harmonic distortion or up to about 50W at low distortion in hi-fi applications.