Hi Bill,

Modified Sine wave inverters (sometimes called modified square wave inverters) are common these days and are considerably cheaper than pure sine wave inverters. Essentially they produce a square wave but with a dwell at the zero crossing point so that the waveform is a crude stepped square wave. A friend uses a 150 watt one with his KN6500 and seems happy. As Chuck mentions you may experience some background noise in your keyboard or amps although my friend hasn't complained about this. A pure sine wave inverter should also be perfectly satisfactory with your keyboard and have no noise problems but will be more expensive. Incidently if you measure the output voltage of a modified sine wave inverter with an ordinary voltmeter the indicated voltage will be about 90 volts not 115. This is not a fault with the inverter but is due to the measuring circuitry in most common voltmeters. The only adverse comment I have seen about modified sine wave inverters is that if used with a laptop for a prolonged period of time the laptop battery pack may be damaged. Whatever inverter you choose it is necessary to ensure that it will supply the initial startup surge current drawn by your equipment.

Cheers
Len C.

[This message has been edited by manorcourt1991 (edited 12-20-2004).]