Multi-stage musical instrument amplifier having distortion modes2009-11-09 00:00:00amplifier stage and the gain modifying circuit
is disconnected from the first amplifier stage. As a result, an output signal from the first amplifier stage has a level which drives the second amplifier stage to provide a substantially linear output signal therefrom. In a second mode, the attenuator
is disconnected from the first amplifier stage and the gain modifying circuit is connected to the first amplifier stage. As a result, an output signal from the first amplifier stage has a level which will overdrive the second amplifier stage to provide a non-linear saturated signal therefrom having a first desired amount of increased harmonic saturation.ClaimsWhat is claimed is:
1. In a preamplifier for audio frequency electrical signals generated by a musical instrument such as a guitar:
a first amplifier stage for receiving electrical signals generated by the musical instrument and providing an output signal;
a second amplifier stage adapted to be driven by the output signal from the first amplifier stage;
means for attenuating the output signal of the first amplifier stage;
gain modifying means for the first amplifier stage; and
switch means for selectively connecting the attenuating means to the first amplifier stage and for selectively connecting the gain modifying means to the first amplifier stage to provide in a first mode an output signal from the first amplifier stage having a level which drives the second amplifier stage to provide a substantially linear output signal therefrom and to provide in a second mode an output signal from the first amplifier stage having a level which will overdrive the second amplifier stage to provide a nonlinear saturated signal therefrom having a first desired amount of increased harmonic content.
2. In the preamplifier of claim 1, said switch means comprising a first switch for selectively connecting the attenuating means to the first amplifier stage and a second switch for selectively connecting the gain modifying means to the first amplifier stage, and which further includes means for controlling said first and second switches whereby in the first mode the attenuating means is connected to the first amplifier stage and the gain modifying means
is disconnected from the first amplifier stage and in the second mode the attenuating means
is disconnected from the first amplifier stage and the gain modifying means is connected to the first amplifier stage.
3. In the preamplifier of claim 1, said first amplifier stage comprising an electron discharge device having a control grid, an anode, a cathode and a cathode resistor and wherein said gain modifying means comprises means for selectively shunt-connecting a capacitor across at least a portion of the cathode resistor.
4. In the preamplifier of claim 3, said attenuating means comprising a resistance adapted to be selectively connected across the output circuit of the first amplifier stage.
5. In the preamplifier of claim 1, further comprising means for modifying, for each mode of operation, the output level of the second amplifying stage.
6. In the preamplifier of claim 5, the modifying means comprising a first mode volume control and a second mode volume control; said switch means comprising a first switch for selectively connecting the attenuating means to the first amplifier stage, and a second switch for selectively connecting the gain modifying means to the first amplifier stage; which further includes a third switch for selectively activating the first mode volume control, and a fourth switch for selectively activating the second mode volume control, and which further includes means for controlling said first, second third and fourth switches whereby in the first mode the attenuating means is connected to the first amplifier stage, the gain modifying means
is disconnected from the first amplifier stage, the first mode volume control is activated and the second mode volume control is deactivated and in the second mode the attenuating means
is disconnected from the first amplifier stage, the gain modifying means is connected to the first amPlifier stage, the first mode volume control is deactivated and the second ...
