| 摘要 |
An audio signal processor, which may be digital, processes an audio input signal to provide an input for a transistor amplifier such that a similar audible effect from the transistor amplifier and loudspeaker combination is obtained as when a valve amplifier with the same audio input signal is used to drive the same loudspeaker. The signal processor achieves this effect by emulating the amplitude distortion of the valve amplifier and the frequency response of the valve amplifier and loudspeaker arrangement. The type of output valve to be emulated, by simulating its transfer function and/or its frequency response, may be selected by use of a knob on the front panel of the amplifier (figure 17). Overload of the loudspeaker and of the power supply may be prevented by a soft limiting circuit (figures 14-16), the circuit also improving apparent loudness. |
