Musical Instrument Preamplifier With Single-Knob Gain and Volume Control
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Solution Overview
Problem
Conventional preamplifiers for acoustic musical instruments require users to manually operate separate input gain and output volume knobs, making it difficult for non-expert users to optimally control sound volume, especially for acoustic guitar players unfamiliar with electrical controls.
Innovation Solution
A preamplifier design featuring a single operation unit, such as a rotary volume knob, that controls both input and output levels through a dual-unit variable resistor and digital signal processing, allowing for automatic adjustment of amplification factors and digital gain processes based on the knob's position, simplifying the control process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If separate input gain and output volume knobs are provided, then the preamplifier can control input and output levels independently, but it becomes difficult for non-expert users to optimally control sound volume
Solution Approach 1:
The patent merges the input gain control and output volume control into a single operation unit (knob 21). By rotating this single knob, users can simultaneously control both the input level (analog amplification) and the output level (digital gain), eliminating the confusion of managing two separate controls while maintaining full control functionality
Solution Approach 2:
The single operation unit (knob 21) serves multiple functions: it controls the analog amplification factor of the operational amplifier for input level adjustment, and simultaneously controls the digital gain process for output level adjustment. This multi-functional design allows one control element to perform what previously required two separate controls
2Ease of operation
If a single operation unit controls both input and output levels, then ease of operation is improved, but the device requires digital signal processing to achieve optimal control
Solution Approach 1:
The system uses the position detection signal from the single operation unit (knob 21) as feedback to automatically determine the appropriate analog amplification factor and digital gain values. The arithmetic processing unit receives the detection signal and automatically calculates the optimal combination of analog and digital gain parameters, eliminating the need for manual optimization by the user
Solution Approach 2:
The preamplifier system automatically adjusts its own analog and digital gain parameters based on the position of the single operation unit. The arithmetic processing unit self-determines the optimal control parameters by processing the detection signal from the knob position, making the system self-adjusting without requiring expert user knowledge
Data Source
AI summary
A preamplifier for musical instruments includes: an operational amplifier 40 to amplify an inputted analog audio signal; a dual-unit variable resistor 30 to change an amplification factor of the operational amplifier 40 by manually operating an operation unit; an A/D converter 51 to convert the amplified analog audio signal to a digital audio signal; and a digital signal processor 60 to digital-signal process the digital audio signal, wherein the dual-unit variable resistor 30 includes a second variable resistor 32 to output a detection signal in accordance with an amount of operation of the operation unit, and the digital signal processor 60 is capable of implementing, based on a value of the detection signal, a first digital gain process to amplify the digital audio signal and/or a second digital gain process to attenuate the digital audio signal.