Abstract: Disclosed is an amplifier for incremental wattage reduction. The amplifier comprises a first pair of pentode vacuum tubes and a second pair of pentode vacuum tubes arranged in a push-pull-parallel power configuration. Each pentode vacuum tube from the first pair of pentode vacuum tubes and the second pair of pentode vacuum tubes includes a plate element, a screen grid element and a cathode element. The amplifier further comprises a single multi-position user switch to configure the first pair of pentode vacuum tubes and the second pair of pentode vacuum tubes to achieve varying wattage outputs of the amplifier by deactivating at least one of the first pair of pentode vacuum tubes or the second pair of vacuum tubes, and causing at least one of the first pair of pentode vacuum tubes or the second pair of vacuum tubes to operate as triodes.
Abstract: An amplifier for electric guitar including a plurality of foot switch selectable preamplifier channels which can be set to provide differing sonic characteristics, and also including a power amplifier section for driving a loudspeaker that can be switched between at least two different power or performance capabilities. User operable switching dedicated to at least one of the preamplifier channels is provided to select preferred power amplifier parameters in conjunction with differing channel voicings. Thus, differing preferred power amplifier characteristics may be pre-set and assigned to individual preamplifier channels and called up automatically in conjunction with the remote channel selection.
Abstract: An electronic amplifying apparatus for sound reproduction and musical instrument amplification including at least two pairs of power output devices which are independently switchable between triode and pentode operation. The amplifier further contains a switch apparatus to select the amount of negative feedback within the amplifier.