Solid state musical instrument amplifier with vacuum tube signal magnitude limiting

摘要

A musical instrument amplifier has all solid state amplification stages but incorporates a pair of vacuum tube signal magnitude limiters to provide vacuum tube type sound when the amplifier is operating in a nonlinear condition. The vacuum tubes are connected to have no supply potential so as to minimize microphonics and are each provided with a small amount of reverse bias to provide a desirable shape of the tube conduction curve and space charge suppression.