DC-Coupled Tube Amplifier Circuit Without Coupling Capacitors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Tube amplifiers using coupling devices like coupling capacitors and transformers introduce distortion and noise, degrading audio signal quality, and require additional components to reduce distortion, which can be costly.
Innovation Solution
A tube amplifier circuit design that eliminates coupling devices by using a three-stage, DC-coupled configuration with a cathode-biased triode, long-tailed pair triodes, and output tubes in a Circlotron configuration, directly connecting tubes to loudspeakers, and incorporating Bluetooth receivers with isolated grounds to enhance sound fidelity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If coupling devices (capacitors, transformers) are used to connect tube stages, then signal transmission between stages is achieved, but distortion and noise are introduced degrading audio quality
Solution Approach 1:
The patent removes coupling devices (capacitors and transformers) from the signal path between tube stages. By directly coupling the plates of input tubes to the grids of subsequent tubes through resistive networks, the invention extracts and eliminates the harmful coupling components that introduce distortion and noise, while maintaining signal transmission functionality.
2Object-generated harmful factors
If additional components are introduced to reduce distortion from coupling devices, then distortion reduction is achieved, but device complexity and cost increase
Solution Approach 1:
The patent converts the traditional approach by eliminating the source of distortion (coupling devices) rather than adding components to compensate for it. The direct coupling architecture uses the tubes' inherent characteristics and simple resistive networks to achieve low distortion without requiring additional correction components, thereby reducing overall device complexity.
3Object-generated harmful factors
If coupling devices are used in the signal path, then impedance matching between stages is achieved, but sound fidelity is degraded
Solution Approach 1:
The patent extracts and removes coupling devices from the signal path, directly connecting tube stages through simple resistive networks. This elimination of coupling components preserves sound fidelity by preventing the distortion and noise that these devices introduce, while the impedance matching function is achieved through the inherent characteristics of the direct coupling architecture.
Data Source
AI summary
An amplifier circuit including a first stage, second stage and output stage. The first stage includes a cathode biased triode. The amplifier circuit includes a second stage having two long tailed pair triodes, each of the second stage tubes output signals inverted from each other wherein the long-tailed pair triodes are direct current coupled to the output tube's grids, Each cathode biased triode section is direct current coupled to one of the two long tailed pair triodes. The output stage includes two output tubes are in a Circlotron configuration with each output tube's cathode connected to the loudspeaker terminals. Each Bluetooth receiver's ground is connected to the ground of the first stage and the output of each Bluetooth is connected to the grid of the first stage.