CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the priority benefit of Japanese Patent Application No. 2018-211790, filed on Nov. 9, 2018. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification.

BACKGROUND

Technical Field

The disclosure relates to a device for providing a distortion effect to an audio signal.

Description of Related Art

In the music field, a solid state amplifier which can switch output levels is known. Such an amplifier can adjust an output level by attenuating an input signal of a power amplifier provided to the final stage. This function is called a power control function. In this method, it is necessary to add musical effects (e.g., distortion and the like) in a stage before a signal is input to the power amplifier.

On the other hand, even in a solid state amplifier, there is a demand for acquisition of distorted tones as in a vacuum-tube amplifier. The vacuum-tube amplifier can obtain a distinctive overdrive effect by being driven at high output. However, a solid state amplifier cannot obtain the overdrive effect even when a drive voltage is increased unlike the vacuum-tube amplifier. As a technology related to this, Patent Document 1 discloses a solid state amplifier capable of adding distortion as in a vacuum-tube amplifier by using a circuit which limits a voltage.

Patent Documents

[Patent Document 1] Japanese Patent Laid-Open No. H08-065062

However, in the amplifier disclosed in Patent Document 1, it is impossible to maintain distortion when the level of an input signal is decreased because a limit value of the voltage limiting circuit is constant. Although it is desirable that a guitar amplifier be able to set a plurality of attenuation factors in accordance with performance scenes such as studios and stages, the same distortion effect irrespective of output levels cannot be obtained in the conventional technology.

The disclosure provides a distortion imparting device capable of obtaining a natural distortion effect even though an output is decreased.

SUMMARY

A distortion imparting device of the disclosure includes: a first amplification part which attenuates an input audio signal on the basis of an attenuation factor set by a user and amplifies the attenuated audio signal; a second amplification part serially connected to the first amplification part; and a limiting part which is connected between an output terminal of the first amplification part and an input terminal of the second amplification part and limits an input voltage of the second amplification part to a predetermined clip voltage, wherein the limiting part determines the clip voltage on the basis of the attenuation factor.

In addition, a distortion imparting method according to the disclosure, performed by a distortion imparting device which provides a distortion effect to an audio signal, includes: an attenuation step of attenuating an input audio signal on the basis of an attenuation factor set by a user; a first amplification step of amplifying the attenuated audio signal; a limiting step of limiting a voltage of the audio signal amplified in the first amplification step to a clip voltage; and a second amplification step of amplifying the limited audio signal, wherein the clip voltage is determined on the basis of the attenuation factor in the limiting step.

