| 摘要 |
A guitar amplifier having an input terminal, an audio output and an audio level controller connected between the input terminal and the audio output. The audio level controller includes a first attenuation path, a second attenuation path having a fixed attenuation and a switch connecting only one of the first or second attenuation paths between the input and the audio output. The switch is preferably controlled remote from the amplifier and preferably by a foot-controlled switch. The first attenuation path is preferably variable. The audio level controller can include a first variable resistor coupled to the input terminal and having a wiper coupled to the audio output, the first variable resistor being coupled to a source of reference voltage through a second resistor to form the first attenuation path, the switch being coupled between the junction of the first and second resistors and the source of reference voltage to provide the second attenuation path. Alternatively, the audio level controller can include a first variable resistor coupled between the input terminal and a source of reference voltage and having a wiper coupled to a first terminal of the switch, a second resistor coupled between the input terminal and the source of reference voltage and having a wiper coupled to a second terminal of the switch, the switch coupling only one of the first and second resistor to the audio output. The amplifier can further include lead mode circuitry in parallel with rhythm circuitry coupled between the input terminal and the audio output.
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