Dual-Path Audio Preamplifier for Distortion-Free Gain Switching
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Solution Overview
Problem
High-end audio preamplifiers face challenges in adjusting audio signal levels without introducing distortion or delay, as existing methods often result in signal degradation or latency.
Innovation Solution
A preamplifier system combining a digitally adjustable symmetric amplifier with a multiple winding coil, where the controller dynamically selects windings to achieve desired gain through relays, ensuring seamless transition between conventional and coil-based signal processing to maintain signal integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional symmetric amplifier with digitally adjustable gain is used, then the gain can be adjusted easily, but distortion and delay are introduced in the audio signal
Solution Approach 1:
The audio signal processing is segmented into two separate paths: a transient adjustment line using a conventional symmetric amplifier for quick gain changes, and a steady adjustment line using a transformer for distortion-free gain adjustment. The system selectively switches between these segments based on operational conditions, allowing easy gain adjustment while avoiding distortion and delay in the steady state.
Solution Approach 2:
A dual-path architecture acts as an intermediary between the conventional amplifier and the final output. The transient adjustment line handles immediate gain changes, while the steady adjustment line processes the signal through a transformer to eliminate distortion. This intermediary structure allows the system to benefit from both approaches without suffering their respective drawbacks.
2Object-generated harmful factors
If a transformer with multiple windings is used for steady adjustment, then distortion-free signal processing is achieved, but the device complexity increases
Solution Approach 1:
The patent merges the conventional amplifier path and the transformer path into a unified dual-line system. Both paths process the same audio signal simultaneously, with the controller intelligently selecting which path to use based on whether the gain setting has changed. This merging allows the system to achieve distortion-free signal processing while managing complexity through intelligent control.
Solution Approach 2:
The system dynamically switches between the transient adjustment line and the steady adjustment line based on whether the gain setting has changed. When the gain is stable, the steady line with the transformer is used for distortion-free processing. When the gain changes, the transient line is used for quick adjustment. This dynamic switching optimizes performance while managing device complexity.
3Speed
If the gain setting is changed frequently, then the system remains responsive, but artifacts are generated during switching between adjustment lines
Solution Approach 1:
The controller monitors gain setting changes and preliminarily determines which adjustment line to use before the actual switching occurs. When a gain change is detected, the controller proactively switches to the transient adjustment line before the steady line would be engaged, preventing artifacts by avoiding mid-transition switching. This preliminary action ensures smooth transitions and eliminates switching artifacts.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively adjusts audio signal levels without distortion or delay, allowing both attenuation and amplification with precise control, ensuring high fidelity and minimizing artifacts.
Implementation Method 1
The steady adjustment line is formed by a coil with multiple windings. The ratio of the number of turns between the primary and the secondary defines the gain.
Data Source
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AI summary
The present invention refers to a high-end audio preamplifier. It is proposed preamplifier system to adjust the level of an audio signal, said system comprising a transient adjustment line and a steady adjustment line receiving the input of the preamplifier system, each adjustment line having an input and an output, a setting device to produce a setting adjustment value, a controller to receive the setting adjustment value and to control the transient adjustment line and the steady adjustment line, a switching module connected an output of the preamplifier system and to the output of the transient adjustment line and the steady adjustment line, the transient adjustment line being made of semiconductors and the steady adjustment line being made of a coil with multiple selectable windings, the controller being configured to : - detect a change of the setting value, - instruct the switching module to select as the output of the preamplifier system, the transient adjustment line output, - adjust the level of the audio signal through the transient adjustment line according to the new setting value, - detect an absence of change of the setting value, - adjust the level of the audio signal through the steady adjustment line according to the new setting value, - instruct the switching module to connect the output of the steady adjustment line and the output of the transient adjustment line with the output of the preamplifier system, - instruct the switching module to connect the output of the preamplifier system only with the steady adjustment line output.